Is Nolasco’s problem the stretch?

I’ve been thoroughly mind-boggled by how Ricky Nolasco could be such a great pitcher peripherally and have such a huge split in FIP and ERA. As we all know, Nolasco bombed badly early in the year in terms of hits and runs allowed, yet surprisingly was still solid when it came to his strikeouts and walks. As the season progressed, Ricky regressed to the mean and his ERA correspondingly dropped. Still, it was a wonder as to why he allowed so many runs while apparently pitching so well. It couldn’t all be the defense’s fault, could it?

Well, a reader on FanGraphs pointed out that there was an interesting disparity between Nolasco’s numbers with the bases empty and with runners on. Usually, I wouldn’t pay too much attention to splits, but of course, pitchers do indeed pitch differently mechanically with runners on or off base. All pitchers pitch out of the stretch when runners are on to prevent runners from taking free bases on them. On the other hand, I’m pretty sure all starters pitch out of the windup when the bases are empty for more deception, among other things.

When you look at Nolasco’s career and 2009 splits with runners on and bases empty, they are quite shockingly different.

I discounted all intentional walks for those splits. The gulf is fairly drastic compared to the 2009 National league average. I think some of that could have something to do with relief values being involved, but the entire thing cannot be explained by just that. The 2009 NL difference in K% was around 2.3%, the difference in “free pass” rate 1%. Nolasco’s career values are around 4% in K% and 0.7% in free pass rate. Perhaps there is something to the idea that Nolasco inherently struggles out of the stretch.

Well, looking at these numbers may not be enough to find out. So for the 2009 season, I gathered up Nolasco’s Pitch f/x data and ran some numbers to find out if there were major differences in how he pitched in the windup and stretch.

First off, a set of definitions for the terms that follow.

Zone%: Percentage of pitches in the static strikezone (from 1.5 to 3.5 feet above home plate and around 1.1 feet to the left and right of the middle of the plate.

Watch%: Percentage of pitches in zone that were taken.

Chase%: Percentage of pitches out of the zone that were swung at.

Whiff%: Percentage of pitches swung at and missed out of total swings

GB%: Percentage of ground balls out of balls in play

These are the definitions that I’ll be using if and when I do more Pitch f/x stuff.

For the data set, I took all of Nolasco’s pitches versus right-handed batters, encompassing 1383 pitches thrown. I took only the right-handed side in order to eliminate the platoon advantage and any biases that may have been brought up. On the other hand, the problem may have been entirely on the left-handed side, so there is need to investigate on the lefty side as well (don’t worry, this will be a two- or three-part set of articles). Data courtesy of MLB Gameday of course. The source from which I retrieved this data was Joe Lefkowitz’ Pitch f/x tool.

I took a look at Nolasco’s numbers above with runners on, bases empty, and overall. Here’s what I got.

It seems obvious, given the fact that pitchers in general seem to pitch worse with runners on/out of the stretch, that their performance in these numbers would decline slightly from the pitcher’s average, and Nolasco does not appear to be any different.

Of the numbers of interest, you can see that the difference in Chase% for Nolasco seems decently high, suggesting that hitters are swinging at 4.5% fewer pitches out of the zone when runners are on then when the bags are empty. The amount of pitches in the zone for Nolasco also drops a decent amount between bases empty/runners on. Those help to explain the falling K%. Interestingly, Nolasco’s whiff rates seem similar in both cases, indicating that if there is a stretch-related issue, it may be about location and not necessarily diminishing stuff. He’s not necessarily missing less bats as much as he is not putting his pitches in the right places.

Another extreme that you can spot in this table is the balls in play. Based on these numbers, Nolasco allowed a much higher rate of balls in play with runners on than he did with the bases empty. This also seems to suggest poorer location. 19.5% of Nolasco’s pitches with men on got in play, in contrast with the 16.4% of his pitches with no one on. The grounder rates also decreased a good deal, suggesting that perhaps the contact was with runners on was also better.

This seems to warrant further investigation. I’m currently working on a look by pitch type and perhaps a similar analysis as the one here against left handers. We’ll wait and see how that turns out. As of right now, my gut says that it could be significant, but it’s too early to say statistically, I suppose. I’ll also be checking on the league averages when I get a chance to compare to Nolasco’s 2009.