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Examining the first start of Marco Gonzales

An in-depth look at the debut start of Cardinals' prospect Marco Gonzales using the data available from

Doug Pensinger

On Wednesday afternoon in Colorado, Marco Gonzales made his first start in the majors in front of friends, family and a large contingent of Cardinals supporters. The start did not go as well as Gonzales would have hoped, giving up five runs in the fourth inning, but held the Rockies scoreless in four out of five frames. After Carlos Martinez made his first start of the season, fourstick did an excellent job analyzing the start using information from Brooks Baseball. This post will copy that format for Marco Gonzales.

Here is the velocity chart from the outing.


He averaged just under 91 miles per hour on his fastball, definitely enough to be successful at this level and solid for a lefthander. The chart helps show what makes Gonzales productive. There is a full ten miles per hour difference from his fastball to his changeup. He threw his fourseam fastball a vast majority of his 82 pitches. Fifty-five fastballs, eighteen changeups and nine curveballs made for his outing on Wednesday.

Here is a chart showing the vertical movement of the pitches.


The issue here is Gonzales' curveball. The average movement was -3.37 inches. Another Cardinals' lefty, Jaime Garcia, averaged -6.64 inches this season. Adam Wainwright's average is -9.02. Comparing Gonzales' curveballs to those guys is unfair, but consider that Shelby Miller's below average offering comes in at -4.75 inches and Michael Wacha's curveball last season came in at -4.96. The mountain air could have hurt Gonzales' break, and it is something that bears watching. Of the nine curves he threw (eight of nine were to lefties), a third were strikes, four were balls, one was fouled off and one was hit for a double. As I mentioned, last season Wacha's vertical movement on the curve was -4.96 and this season it is -6.31.

Gonzales has a reputation as a command specialist. He did walk two hitters, but was generally around the strike zone to both lefties and righties. Here is the zone map against lefties.

Here is the same one against righties.

Gonzales pitches inside to righties and outside to lefties. Here is the same information from innings 1-3 and five.

Now here it is from the fourth inning when the Rockies batted around and scored all five of the runs that Gonzales allowed.

There is not a big difference in the location between the two charts, but he ended up with vastly different results. In the second chart there is not a single swing and miss. After having gone through the lineup, the Rockies players were able to adjust, fouling off the pitches below the strike zone when before they had been swinging and missing. Whether Gonzales can turn over a major league lineup is something to watch for when he starts against the Giants on Tuesday.

Gonzales was drafted in the first round and made it to the majors in just a year based on the strength of one really good pitch, the changeup. As a lefty, he has the ability to neutralize right-handed hitters who he will see a majority of the time. He can then use his natural platoon advantage against lefties even though he does not have a plus pitch to use against them with the changeup not as strong against lefties. He did give up a home run to Drew Stubbs on a changeup, but overall, it was a very effective pitch. Fifteen of Gonzales' eighteen changeups were served to righties. He induced eight swings. Of those eight swings, 50% resulted in a swing and a miss. Just two balls were hit into play, and only one resulted in a hit.

Gonzales did not have the outing he hoped for in his first major league start and his curveball was not very effective, but his changeup is an excellent pitch that will serve him well in his continued audition in the majors. The Cardinals saw enough to give him another start on Tuesday, and he may stay a bit longer as Joe Kelly continues to rehab. Gonzales is not a finished product, but he is already good enough to get hitters out in the majors just one year from college which would seem much more remarkable if Michael Wacha had not stolen his thunder by doing the same a year ago. What Gonzales did is rare, and he should not have to suffer outsized expectations just because we have been spoiled by Michael Wacha.