With the Atlanta Braves fighting for a playoff spot in the crowded National League East, any assistance they can get without having to trade away talent is a plus towards achieving that goal. They added just that kind of help back to their roster this month when Mike Gonzalez, who missed almost all of the 2007 season due to Tommy John surgery, made his season debut on June 18. Between the ongoing issues with keeping Rafael Soriano in action, the loss of Peter Moylan for the year, and the bouncing around where John Smoltz moved from the rotation to closing and finally to the Disabled List for the remainder of the season, having a pitcher of Gonzalez’ ability fall in your lap should be considered a gift. Of course, this assumes that Gonzalez is capable of being the dominating force he was before his injury trouble. Today, we’ll take a look and see if that’s the case today.

Michael Vela Gonzalez was drafted by the Pittsburgh Pirates in the 17th round of the 1996 amateur draft, but he declined to sign. The Pirates were persistent though, and selected him once again the next year, this time in the 30th round. Gonzalez signed on that time around, and was placed in the Gulf Coast League at age 19 before moving on to the Sally League. He began his career a starting pitcher. In his early years in the low minors, Gonzalez was a dominating strikeout pitcher who, as he moved up to face more patient and experienced hitters, had trouble keeping his walk totals down. Despite struggling with his control over 20 starts at High-A Lynchburg in the Carolina League, the Pirates moved the 21-year-old Gonzalez to Double-A Altoona, where he walked 6.4 hitters per nine along with 10.5 K/9. Gonzalez lost some of that “new prospect” vibe in 2000, when he had to undergo arthroscopic shoulder surgery, but he was able to rebound, throwing 62 innings between two levels that same season.

Gonzalez was not considered a significant prospect for most of the time he spent in the minor leagues. It was not until 2002 that Baseball America ranked him within their organizational top 30 for the Pirates-just sneaking him in as No. 30-due to a solid stint in the Arizona Fall League. It’s a good thing for Pittsburgh that Gonzalez succeeded when he did, because they put him on the 40-man roster in time to avoid losing him to the Rule 5 draft. The fact that he struck out batters at such a high rate on top of his being a left-hander would have made him an attractive high-upside pick, especially with his tendency to keep the ball in the park-over 601 2/3 minor league innings pitched, Gonzalez had allowed just 0.6 HR/9-and his lack of refined secondary stuff made him more suitable for a role in the bullpen. He had his second arthroscopic surgery, this time on his knee, during the 2002 season, cutting short his time on the mound.

Baseball America would move Gonzalez up to the Pirates’ ninth-best prospect in their organizational rankings following his shortened 2002 campaign. Outside of his walking five per nine, he was impressive thanks to his striking out nearly one batter per inning while allowing only 0.4 HR/9. The Pirates moved Gonzalez to the pen full-time for the 2003 season, since he continued to have issues with his command and needed to refine his changeup, which at that time had promise but was still not where it needed to be. This turned out be an awkward season for Gonzalez: he pitched for five different teams in the minors because of back spasms that kept him in extended spring training, but he also had to deal with being involved in a pair of trades. He was traded both to and away from the Red Sox in a 10-day span, and accrued just 34 1/3 innings pitched total thanks to all of the moving around. Gonzalez was dealt along with Scott Sauerbeck to the Red Sox in exchange for Brandon Lyon and Anastacio Martinez, but then the Pirates claimed that Lyon’s elbow was damaged goods, and the deal was reworked before the trade deadline ended, with the Pirates receiving one of their top prospects back.

Gonzalez’s 2003 made him seem like a project waiting to be fixed, as he had an equal number of walks and strikeouts during his short major league stint. His 2004 season would change all of that, though:

Year Team               IP   K/9  BB/9   K/BB   HR/9    H/9   QERA
2004 Nashville(AAA)   20.0  15.8   3.2    5.0    0.0    5.4    -
2004 Pittsburgh(MLB)  43.1  11.4   1.3    9.2    0.4    6.7   1.66

Gonzalez’s explosion onto the major league scene is reflected in that QERA of 1.66, because it tells you that his 1.25 actual ERA was no joke. He would pitch with much of the same effectiveness the next two seasons, though the ridiculous K/BB ratio would not come with him; Gonzalez’s problems with command returned. Even so, because of his ability to keep the ball in the park, he was able to overcome the walks and post QERA figures of 3.99 and 4.04. His career HR/FB is a very low 6.6 percent, and that’s inflated due to a rough rookie season in 2003, and by his injury-handicapped 2007, when he was missing plenty of velocity on his pitches.

Gonzalez was traded to the Braves along with Brent Lillibridge in the Adam LaRoche deal, a deal that hasn’t produced much for either side as of yet-Lillibridge is just now putting together some major league at-bats, and LaRoche’s back troubles have all but sapped his power in Pittsburgh. Gonzalez has also had to deal with another major injury, as he underwent Tommy John surgery, and is just now returning to action. It takes time for a pitcher’s command to come back after the ligament replacement surgery-although the idea of Gonzalez giving up more walks might seem “inconceivable!”-but if Gonzalez can continue to rack up strikeouts and keep the ball in the park, he’ll be a major boon to the beleaguered Braves bullpen.-Marc Normandin

Performance Evaluation

Unfortunately, Mr. Gonzalez timed his injury well enough to miss the development of the Pitch F/X system. Just half of his eighteen appearances in 2007 were recorded, and among those, a few were missing data, meaning that there is next to nothing which we can use in an analysis of how Gonzalez performs. Even if we were to explore his 2007 numbers, setting aside the question of how his eventual injury affected his performance, small sample-size syndrome would be in effect. (The same can be said of his statistics this season.)

Feeling a bit creative, I bought Gonzo’s 2006 data from Baseball Info Solutions. The dataset does not offer the same perks as Pitch F/X, such as movement, but it captures velocity and location as well as provides the pitch type sans classification algorithms or spin analyses. For starters, here are his overall numbers in terms of pitch usage and velocity:

Pitch    Velocity  Percent
Fastball   92.23     65.3
Slider     80.97     33.0
Change     81.07      1.6

So, Gonzalez is primarily a fastball/slider guy, but do these percentages break down at all against right- and left-handed batters?

Hitters   FB%   SL%   CH%
vs. LH   70.7  28.4   0.4
vs. RH   62.3  34.8   1.9

Some of his pitches were not identified or lacked velocity readings, but he seems to heavily favor his heater against lefties, while throwing more sliders and a sprinkling of changeups to righties (against lefties, there was only one recorded changeup).

What about his results on these pitches, broken down by handedness?

                        Called   Swinging
Hitters  Ball%  Foul%   Strike%  Strike%   BIP%
vs. LH   35.3   15.8     21.4     15.8     11.1
vs. RH   38.2   19.8     16.1     10.2     14.8

Opposite-handed hitters swung and missed less often, therefore making more contact, and ended up putting a higher percentage of balls in play. Not surprisingly, these right-handed hitters produced a higher OPS of 600, against the 521 generated by lefties against Gonzalez. Home runs were excluded from these results, but he surrendered just one all year, so we’re not really taking about a exclusion with any statistical impact.

Using projections for that 2006 season, I classified hitters as either power or contact hitters based on their projected slugging percentage. Everything here was relatively similar given the 953 total pitches recorded in 2006, but here are the results:

                             Called   Swinging
Hitters       Ball%  Foul%   Strike%  Strike%   BIP%
vs. Power     37.1   18.5     17.8      11.1   14.7
vs. Contact   39.9   19.5     16.5      11.9   11.9

Lastly, did Gonzo have a discernible approach with regards to location? Separating his pitches into three general zones, here are his location percentages broken down by batter handedness:

Hitters   Away%  Middle%  Inside%
vs. LH    44.7    32.6      22.7
vs. RH    25.1    28.6      46.3

“Inside” and “Away” constitute pitches on the corners of the strike zone as well as all those out of the zone. Due to the overall small number of pitches, the results would not be nearly as significant if broken down into further subgroupings based on whether they were up or down. Despite throwing virtually the same percentage of pitches within the middle zone, he favored the outside corner against lefties and the inside corner against righties. In light of his surgical history, it will certainly be very interesting to keep tabs on his numbers to see if anything changes this year.-Eric Seidman

Health Report

From a health standpoint, Gonzalez is really no different than many pitchers. Questionable mechanics led to Tommy John surgery, which in turn returned him to health just enough to be effective and put him in a position to hurt his arm some more. Gonzalez uses the same complex mechanics that led him to arm troubles (and success) after surgery, showing no real changes.

Why complex? Gonzalez’s motion can be thought of as a series of steps rather than a flowing motion. At each step, Gonzalez loses momentum rather than passing it through the kinetic chain that goes from the foot to the fingertips. Gonzalez has been able to overcome this inefficiency through brute force and an electric arm. His leg drive is extremely strong, or at least appears as such (Gonzalez has never been tested on a force plate). Where Gonzalez creates problems for himself is in his “high ready” position, where his arm accelerates forward so rapidly that he forces the elbow both back and often to the side, placing an inordinate, and ultimately untenable load on his ulnar collateral ligament. Eventually, under repeated use this way, it broke.

With a new ligament but old mechanics, Gonzalez is a bit of a ticking time bomb. He’ll be effective, but we’re not sure for how long. Previous studies have shown that there appears to be a Tommy John “honeymoon,” a period of five years where a new ligament seldom breaks. This isn’t always the case, but it’s enough of a rule to allow for exceptions. Some clinicians have speculated that the new ligament is strongest as its undergoing “ligamentization,” the process by which the transplanted tendon not only takes over the function of the replaced ligament but also takes on some of the biological signatures of a ligament. No one is sure why this occurs, though the human body is in a constant state of replacing old cells with new ones. Somehow, the body senses what should be there rather than what is, and it adjusts.

One note that kept coming up in talking to experts about his condition was that Gonzalez’s ligament injury may not have happened in the typical insidious fashion. Instead, Gonzalez came out of a game, said he had no pain, but shortly after he suffered a severe spasm. The elbow was imaged and showed “no structural damage,” but less than a week later he was scheduled for surgery. The cause of the spasm was never determined, though most pointed to some sort of fatigue. If this is the case, even in the “honeymoon,” there could be a recurrence, putting Gonzalez at a slightly higher risk than normal.-Will Carroll

Scouting Report

Kiley McDaniel of When healthy, Gonzalez has made his living the last five seasons with plus stuff, for anybody, not just for a southpaw. When he’s on, Gonzalez works off of a four-seam fastball that comes in consistently at 92-94 mph with good late sink and glove-side ride. His slider is a legitimate out-pitch with two-plane break that comes in at 80-82 mph. Both his fastball and slider grade as at least a 60 on the 20-80 scouting scale. Gonzalez uses both of these pitches with late sinking action to create groundballs, and they do when Gonzalez commands them well. That’s the catch, though: Gonzalez’s command is average at the best of times, and it comes and goes. As is usual with pitchers just returning from Tommy John surgery, his command isn’t all the way back yet, but it wasn’t exactly good to begin with. While the fastball velocity and bite on his slider are back, the movement on his fastball isn’t what it used to be. The command and the life on his fastball are both expected to return, but Gonzalez is relying on his prior closing experience, veteran savvy, and raw stuff for the time being.

Eric Seidman is a contributor to Baseball Prospectus. He can be reached here.