Jon Lester has made headlines each of the past few seasons, but this is the first year that he’s garnered attention due to his performance as a major league starting pitcher. Prior to the end of the regular season, Red Sox announcer Jerry Remy stated that Jon Lester was the best pitcher in the Red Sox rotation, and based on his performance both this season and in the playoffs, it’s a tough position to argue against. How did he get to this point, and will he able to keep it up in the future?

Jonathan Tyler Lester was selected by the Red Sox in the second round of the 2002 amateur entry draft as their first overall pick, since they lost their own first-rounder due to the free-agent signing of Johnny Damon. He was a standout basketball player at Bellarmine Preparatory School in Tacoma, Washington, and in addition to pitching, he was also a first baseman. The 18-year-old was given a $1 million bonus to sign with the club, the largest of anyone selected in the second round, and was assigned to the Gulf Coast League Red Sox to start his professional career. Since he didn’t sign until mid-August, Lester was able to pitch just 2/3 of an inning total, and would have to wait until 2003 to do anything substantial.

Baseball America would rate Lester as the eighth-best prospect in the Red Sox organization, comparing his athleticism to that of Mark Langston, and saying that “his fastball has room to grow because he has a projectable body and easy arm action.” In addition to the fastball Lester had a changeup, and his curveball had improved during instructional league, though it was a pitch that still required refinement. His first full season in the minors went well, though it was obvious that Lester was still raw and needed more experience to develop his repertoire and approach. He posted a 3.65 ERA, but struck out just over six hitters per nine while walking 3.7 in 106 innings pitched. It was certainly good for a 19-year-old, but he suffered from tightness in his shoulder early on in the season, and, in a move reminiscent of the Dodgers‘ handling of Clayton Kershaw this year, he was kept on a strict pitch count for most of the season.

Baseball America would rank Lester eighth-best in the Sox system again for the 2004 season, saying that he was ready for High-A, but was still at least 2½ years away from the majors based on his raw stuff. Baseball Prospectus 2004 sang the same tune, saying “As a tall left-hander with good command and composure, he has the smooth repeatable delivery that scouts love. He’ll need to improve his peripheral numbers to find success as he climbs the ladder.” Lester would do just that pitching in the Florida State League; though his ERA was 4.28, he had a better season with 9.7 punchouts per nine to go with 3.6 BB/9 over 90 1/3 innings pitched. His velocity increased slightly, and he spent more time at the high end of the 88-93 mph spectrum he had flashed in his career, increasing his strikeouts significantly.

That was good enough to rate Lester the fourth-best prospect in an absolutely stacked Red Sox system-along with the lefty, the Red Sox had Hanley Ramirez (ranked first), Jonathan Papelbon (third), Anibal Sanchez (fifth), Dustin Pedroia (sixth), and Kelly Shoppach (eighth) in their top ten. Baseball America said that Lester had a “stronger arm” than most left-handers, as he had the ability to touch 96 and lived around 92-93 with his fastball. They also gave the cut fastball that he picked up midseason credit for his massive improvement after jumping a level, but stated that he also needed to refine his secondary pitches in order to earn a slot in the Boston rotation.

Lester would move to Double-A Portland for the 2005 season, and there he would open some eyes to his ability: 148 1/3 innings pitched, 9.9 K/9, 3.5 BB/9, just 0.6 HR/9, and just 6.9 H/9. He led the league in ERA, complete games, and strikeouts, and was named both the Boston and Eastern League pitcher of the year, thanks in part to the increased velocity on his fastball and cutter. This would make Lester an attractive prospect for other teams; the Rangers had already made a move on the southpaw when the two clubs were talking about sending Manny Ramirez to Texas in exchange for Alex Rodriguez, and before the 2006 season, the Florida Marlins wanted him packaged in the Josh Beckett trade. Considering how things have gone down for the Sox since that initial non-deal, it’s a good thing they chose not to move Lester.

If not for the brief presence of Andy Marte on the Red Sox roster, Jon Lester would have been the top prospect on the team heading into the 2006 season. Baseball America stated that his cut fastball had morphed into a “true slider,” and that Lester had the potential for three plus pitches. Lester was able to get both swings and misses and called strikes with his changeup, and the consensus was that he still needed a little tweaking, but would be ready for a major league job by the second half of the year. Baseball Prospectus 2006 agreed, saying that Lester would “start the year in Pawtucket, but might not need a full season there.”

Lester’s 2006 was full of ups and downs. First, there was the good, as Lester handled Triple-A respectably enough for a 22-year-old, with 8.3 strikeouts per nine, but a few more walks than you would like to see at 4.8 per nine. Due to injuries and ineffectiveness in the Red Sox rotation-this was a club that had to put Kevin Jarvis in uniform, after all-Lester made his way to the big leagues, and he would not disappoint, even if his peripherals needed some refinement: 6.6 strikeouts per nine with just 0.8 homers per nine, but he did continue walking far too many hitters at 4.8 BB/9. That stretch was broken into two distinct phases though; the first, a run of seven starts where he allowed no more than two runs per game, and the second, a poor showing in five of six starts that boosted his ERA considerably.

His season would be cut short for reasons out of his and the Red Sox’s control; first, Lester would miss time due to a strained back that was suffered during a car accident in August, but it would later be revealed through testing that he had anaplastic large cell lymphoma, a treatable form of cancer. He began chemotherapy, and was in remission by mid-December of the same year. Forgetting his profession for a moment, Jonathan Lester was now a cancer survivor thanks to a little luck in finding out about his condition while it was still early enough to be handled effectively and quickly.

In baseball terms, though, the Red Sox had to find a way to bring their top pitching prospect back to the majors at a pace that he could find his rhythm once again. Lester would pitch at four levels in 2007, starting out at Low-A Greenville, moving back up to Double-A Portland for a brief time, and then ending up in Pawtucket, where he would throw 71 2/3 innings. Though the quality of his pitching wasn’t what it was prior to the cancer scare, Lester was still effective, with 6.4 strikeouts per nine and 3.9 walks per nine, along with his ever-present low homer rate (0.5 per nine).

The Red Sox would need the services of Lester before year’s end, and, despite just coming off of cancer treatment and slowly working his way back through the minors, he would toss 63 innings in the majors (and 153 2/3 total on the year). Unsurprisingly, Lester was still adjusting to the big leagues-he was having trouble prior to being shut down in 2006, after all-and though he struck out over seven batters per nine, his walk rate (4.4 per nine) was more than a little iffy, and his home run rate was uncharacteristically poor at 1.4 per nine.

Lester would end up on the ALCS roster against the Cleveland Indians, and he would come in to pitch two games in relief, going 3 2/3 innings with two earned runs, five punchouts, and a single walk allowed. Though pitching in the playoffs after a battle with cancer was an emotional thing for both Lester and all those watching, his starting in the clinching Game Four of the World Series for the Red Sox was the ultimate finish to his return to the major leagues, an achievement that stands out not just because the Red Sox came away victorious, but because Lester had managed to come back and succeed on the sport’s biggest stage. It’s something I won’t soon forget, and I’m certain I’m not alone in that.

To return solely to performance, Lester still needed some work in order to return to the potential he was capable of prior to 2006. His PECOTA forecast had some impressive up-side projections, but his weighted mean was more in line with his 2007 performance. A month into the season, it looked as if it was going to be a long year for the lefty; Lester had just 12 whiffs against 16 free passes over his first 27 2/3 innings. However, a start against Roy Halladay to finish up the month saw him change his approach noticeably. Jerry Remy spoke of this during the season, that Lester had taken a page out of his opponent’s book that night, and made a point of working faster and attacking hitters more often-though he was throwing the same number of pitches per plate appearance, he was more in control of the at-bat, something you’ll see supported by data later on. From that Halladay match going forward, Lester was a completely different pitcher, cranking out 6.9 strikeouts per nine, a new, nicely low 2.6 walks per nine, and his more characteristic 0.5 homers per nine, along with a 2.82 ERA.

Lester has been the key to the Red Sox rotation in the playoffs this year, and he’s probably the pitcher Red Sox fans are most comfortable with taking the mound. His first start against the Rays in this series comes today, against a tough opponent to boot; if there’s one thing Lester has shown us over the years though, he’s capable of pitching under pressure, something he was known for even during his days in the minors prior to his battle with cancer.-Marc Normandin

Performance Evaluation

In baseball, it can be quite difficult to shake a reputation. Iit would probably take Alex Rodriguez six years of solid post-season performance before anyone would believe that he possesses some innate clutch ability. I bring this up only because, entering this year, Jon Lester was generally thought of as more of a cancer survivor with potential than as a solid member of Boston’s starting rotation. After his performance this year, however, he has broken free of that pre-season tag and is now considered the ace of their staff. A lefty with a 93 mph fastball who shakes things up with a cutter, curveball, and occasional changeup, Lester tore through the competition this season en route to a 3.21 ERA and 3.64 FIP in 210 1/3 innings.

He did cross the Verducci Line this season, as his innings pitched vastly exceeded the 127 combined innings in 2006 and the 90 2/3 combined innings last year. Despite this, he has shown no indication of fatigue; September was his best month of the season, with a 2.14 ERA in five starts, and he pitched 14 scoreless innings with three walks and 11 strikeouts against the Angels in the division series. Terry Francona has already pegged Lester as the Game Three starter against Matt Garza today in Boston. Though home/road splits are perhaps more useless than helpful in predicting performance-just ask Ryan Dempster-Lester did perform much better in the friendly confines of Fenway Park than on the road. In 17 home games, he posted a 2.49 ERA and 2.5 K/BB ratio; on the road for the other 16 starts, a 4.09 ERA and a 2.1 K/BB ratio. A 4.09 ERA is still pretty solid in the American League, so it was not as if he suddenly turned into Livan Hernandez or Kip Wells, but he definitely experienced a drop-off of some sort.

Lester absolutely manhandled lefties in 253 plate appearances, holding them to a .217/.269/.302 line, and just 14 extra-base hits (three of them home runs). While we would expect a lefty to shut down like-handed hitters, Lester’s splits in both 2006 and 2007 were not nearly as drastic in favor of left-handed domination; in ’06 he actually handled right-handers better, despite the small sample size. One of the reasons for his success this season involved working ahead of hitters, evidenced by the number of plate appearances that reached certain counts. Lester stayed ahead of 62.6 percent of the batters he faced, which allowed him to work inside without fear of losing the hitter. Few pitchers worked inside as often as Lester this season.

His opponent on Monday, Matt Garza, was the beneficiary of plenty of bullpen support, which massaged his numbers into a much better shape than they actually were. While Lester’s support from the pen was not as dramatic, it was still quite high; the Red Sox relief corps prevented close to three runs more than an average bullpen would have prevented, which definitely helped generate Lester’s 3.21 ERA. Not that these runs, had they scored, would have elevated the ERA to 7.67 or anything along those lines, but it is noteworthy that he did have significant support along the way.

Unlike Garza, however, who faced some of the stiffest competition at the plate in the American League, Lester’s quality of opposition OPS was 38th out of the 57 starters in the league with at least 120 innings. Four of his starts came against the 23rd-ranked Blue Jays in the team EqA, and another four against the 29th-ranked Athletics. This becomes noticeable when we see that his SNVAR of 6.0, which is third in the American League to just Cliff Lee and Roy Halladay, translates to a 6.4 SNLVAR. The 6.4 SNLVAR still ranks third, but it did not increase much with the marginal value of the lineups faced incorporated, because the competition he faced was not so stiff.

In 2006 and 2007, Lester’s ground-ball/fly-ball ratio was 1.08 and 0.73 respectively, but it jumped up this season to 1.49. Generating plenty of ground balls on a team with the fifth-best defensive efficiency in baseball results in plenty of extra outs. Lester’s increased usage of a cutter seems to be a major underlying reason for this increase, along with his ability to locate less pitches up in the zone than in the past. It would have been hard to believe back in April, when he made seven starts with 23 walks and 22 strikeouts and a 4.31 ERA, that come October he would be the hottest pitcher going, but that is indeed the case.

Against Tampa Bay in the regular season, Lester made three starts, holding the Rays to just two runs over 20 innings for a 0.90 ERA and a K/BB ratio of 3.17. He is clearly a star pitcher in the making, and in a series during which home-field advantage will likely loom large, Lester will be relied upon in Game Three to continue his domination of the Rays at Fenway. Should he reproduce his 2008 campaign for the next several years, the sky could be the limit for the flame-throwing lefty.-Eric Seidman

Eric Seidman is a contributor to Baseball Prospectus. You can contact Eric by clicking here.