Baseball is about learning from one’s peers. I think that’s true for professional baseball players, as well as for baseball writers. Just as players talk shop in the bullpen or in the batting cages, my knowledge of the game and my writing abilities have both been augmented by the other writers at Baseball Prospectus, past and present. Despite the banter and jokes, we regularly come to one another for advice and to hash out new ideas.

As such, our own Ben Carsley and Craig Goldstein have long been fans of Carlos Martinez, ranking him in the top 70 of their U25 dynasty players last year—even with his early big-league struggles causing many to sour on him.

I was one of those people who didn’t believe Martinez would find success this year as a starter. The arm strength and fastball/slider were impressive in 2014; however, I couldn’t overlook Martinez’s massive platoon split. A year ago, lefties hit .289/.387/.462 and walked more than they struck out against the right-hander—and that was largely out of the bullpen, where Mike Matheny could conceivably shield his pitcher from unfavorable matchups. Sure, he was just 22 years old last season, but that seemed to be a tire fire waiting to happen in the starting rotation.

Craig regularly echoed his belief in Carlos Martinez over the past two years, a belief that stemmed from a seldom-used changeup that flashed promise. While I lamented Martinez’s struggles against lefties, Craig and Ben focused on the underlying developmental process. One Martinez committed to his changeup, the argument went, more success against lefties would follow.

It’s interesting that I somewhat dismissed that analysis as veiled hope, as I wrote a piece in April on Shane Greene that grounded its argument in the sudden development of a changeup over the offseason. While my small-sample analysis on Greene has proven wholly incorrect and somewhat laughable as the season has progressed, Carlos Martinez has committed to his developing changeup and has experienced marked improvement. In fact, it’s perhaps the biggest reason why he’s sporting a sparkling 2.52 ERA through 107 1/3 innings.

Martinez’s struggles against lefties in 2013 and 2014 have not been overblown. Opposing lefties hit near .300 during that timeframe, getting on base near 40 percent of the time, and only striking out in roughly 11 percent of plate appearances. The following table illustrates the drastic improvement for Carlos Martinez against left-handed batters:

























While the walk rate remains an issue, Martinez has erased his platoon problems that had plagued him throughout his first two years in the majors. Righties are hitting .222, while lefties are only a single point higher at .223. Righties are striking out at a 27.3 percent clip, with lefties at 23.8 percent. In short, Martinez has always been nasty against right-handed batters. He’s just now figuring out how to attack lefties with success.

And that comes with trusting his changeup. The Dominican Republic native has essentially doubled his changeup usage from 2014 to 2015 (numbers courtesy of Brooks Baseball).

Description: CarlosMartinez_PitchSelection.png

The vast majority of that increased usage has come against lefties. In 2014, he threw his changeup 17 percent of the time to left-handed batters. That number has jumped to 29 percent this season. Furthermore, reflecting the trust Martinez has developed in el cambio, he’s finally throwing more changeups when ahead in the count, rather than sliders and fastballs, as he did a year ago.

The right-hander now understands that his changeup serves as his put-away pitch against left-handed hitters. This can be seen in his whiff rates against lefties over the past three years.

Description: CarlosMartinez_LeftyChangeup.png

A year ago, Martinez threw his slider most often to lefties when ahead in the count. This is depicted in his 18.84 percent whiff rate against lefties with his slider in 2014. The transition from his slider as his go-to put-away pitch to his changeup in 2015 is shown in the decreased whiff rate of his slider and the dramatic uptick in his 24.59 percent whiff rate on his changeup. When he’s facing a lefty with two strikes, he throws his changeup 41 percent of the time, 11 percentage points more than any other pitch.

As mentioned above, this improvement against lefties has combined with his continued effectiveness against righties to bring overall success. His 2.52 ERA is 12th-best among qualified starters, and he’s been even better as of late. His 1.60 ERA over the past 30 days is sixth-best in the league. Martinez has nearly been a Holy Grail pitcher (better-than-average in strikeout, walk, and ground-ball rates) in the last 30 days, in fact, as his walk rate of 2.94 BB/9 is barely worse than the league-average. This is just serving as more evidence of his recent success.

The question, of course, is whether Carlos Martinez can continue his dream season. His 3.70 DRA suggests he actually hasn’t been as good as advertised; however, his 94 cFIP projects him to be six-percent-above the league’s average throughout the remainder of the season. One could perhaps nitpick his .287 BABIP and how it’s nearly 50 points lower than any other year—and that’s perhaps partly what DRA doesn’t like—but one would also expect his BABIP to drop if he’s missing more bats and inducing more grounders against lefties.

Martinez is ultimately taking the jump forward in development at which scouts had hinted for the last few years. He’s no longer a two-pitch guy with a changeup that flashes. He’s a three-pitch starter who can increasingly handle opposite-handed batters. Of course, the command needs to improve for the 23-year-old hurler, but that’s hardly a surprise given his position on the hypothetical developmental curve.


For fantasy owners, the best course of action is likely to “hold” on Carlos Martinez. This isn’t a call that’s based upon his talent, but rather where his stock currently resides. Anyone seeking to buy C-Mart will have to pay a king’s ransom. He’s one of the hottest young pitchers in the game at the moment and ain’t going to be acquired for a reasonable package. Anyone trading for Martinez will have to overpay, likely by a significant amount. That just isn’t smart business.

On the flip side, owners who have the right-hander on their roster should shy away from selling. This isn’t a 23-year-old who is performing far above his ability level. Instead, this is a 23-year-old who is beginning to find his legs at the big-league level. He’s developing into a more well-rounded pitcher who can help anchor the Cardinals’ stellar pitching staff. The ERA will climb a bit in the second half, simply because it’d be nuts to project a mid-2.00 ERA for a non-ace, but his current profile doesn’t suggest that an implosion is imminent. Martinez has a chance to be a top-of-the-rotation pitcher, and he appears to be scratching at the surface of his potential. Selling on a pitcher at that stage of development isn’t wise. Hold tight and continue to enjoy the fantasy production.

Thank you for reading

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any worry about a move back to the bullpen to keep his innings under control?
I think this is a fair question and one that I hadn't considered when writing this. Rumors early in the season suggested that C-Mart would be on a limit of roughly 150 innings. I doubt they hold fast to that number -- given his performance -- but it's a legitimate concern that would give more weight to trading him away in single-season redraft leagues. I don't think it matters in dynasty formats.