Adam Wainwright and his decreased strikeout rate in 2014

All things considered, St. Louis Cardinals ace Adam Wainwright had a successful 2014 season. Back in November, Aaron Finkel looked at how Wainwright performed compared to preseason projections, and for a second season in a row, he eclipsed 200 innings and posted an ERA that ranked in the top three of the National League. However, 2014's success didn't necessarily come easily to Wainwright. During his media session at this year's Winter Warm-Up, he shared some valuable insight on the health of his throwing elbow as the season progressed (the full video by Derrick Goold can be found here):

"At the end of the year, the full extension was the problem...You saw me throwing a lot of cutters and a lot of curveballs cause I could get my arm to go this way [right to left] fine. I just couldn't get it to pronate all the way through...And that's okay because I'm not really a power pitcher, so I was able to get by with that. You saw the difference in the first half of the year when I was a complete pitcher. I was doing all the things I wanted to do and the second half of the year when I couldn't."

For a pitcher that relies on the craftiness of a extremely deep repertoire, a limited arsenal can be a huge detriment to success. Fortunately for the Cardinals, ace Wainwright was able to work through it for the most part, especially in September when he won all five of his starts and averaged nearly eight innings per start. The presence of a supreme curveball is one of the driving forces behind Wainwright's ability to "push through" last season.

However, despite having a good year on the surface, it was riddled with inconsistency, and it carried over to his first two outings in the playoffs. One of the biggest reasons for his inconsistency was a decreased strikeout rate as he dealt with a three percent drop from the 2013 season (down to 19.9% from 22.9%). The following is a table showing his strikeout and walk rates by month in 2014:

The strikeout rate suffered most immediately after it was reported he was dealing with elbow tendinitis. Using BrooksBaseball, let's take a closer look at Wainwright's repertoire during these three distinct time periods.

2007 through 2013

As we are all well aware of by now, Wainwright is not, by any means, a "power pitcher," but from 2007 through the end of the 2013 season, he went to one of his two fastballs ~48% of the time, with his ~91 MPH sinker being his most-used pitch. His most success clearly came from his curveball, but Wainwright enjoyed "swing and miss" success with both his fourseamer and cutter as well. In fact, from a results standpoint, his fourseamer and cutter were his second and third most effective pitches behind his all-world curveball.

2014 pre-tendinitis report (March 31, 2014 to June 10, 2014)

2014 post-tendinits report (June 11, 2014 to October 16, 2014)

The pitches most affected by not being able to "pronate all the way through" are his sinker, his changeup, and to an extent his fourseamer. Well, the data backs up what Wainwright had to say as he went from throwing his fourseamer, sinker, and changeup ~54% of the time (from 2007 through 2013) to ~40% after his elbow tendinitis was first reported. A 14% drop is not insignificant by any means, and it shows that there was definitely something inherently wrong.

However, upon further review of velocity but especially horizontal movement, I uncovered no significant difference in either aspect as compared to what it was from 2007 through 2013. Thus, while Wainwright was clearly experiencing a considerable amount of discomfort throwing pitches that required pronation, there were no apparent negative effects on the pitches from a process standpoint (i.e. same velocity, same horizontal movement). Yet, despite having virtually the same velocity and horizontal movement, Wainwright experienced a decrease in whiff percentage on his fourseamer and his cutter, by ~2% and ~3%, respectively. This undoubtedly played a key role in his decreased strikeout rate.

Bottom line

For Wainwright to be an effective pitcher over the course of 200-plus innings (and for the rest of his career), he is going to need his full repertoire of pitches. When starting pitchers start striking out hitters less (by missing less bats), it usually signifies the start of their decline. Wainwright's curveball and cutter can be extremely effective pitches for him, but over time (especially the third time through the order and late in the season), hitters can "sit on" these two pitches with his fastballs pretty much out of the question. It is pretty clear that Wainwright's consistent success is largely dependent on his establishment of his fastballs early in games, subsequently helping set up his put-away pitches (i.e. curveball, cutter).

For the sake of the Cardinals, let's hope this offseason's "elbow scope" puts Wainwright in a position to be "all systems go" come opening night against Jon Lester and the Cubs on ESPN. In closing, the usage rate to look for is ~45% (or higher) with his fastballs (combined). If he is able to get there, Waino will have another successful season in 2015.

Credit to Fangraphs and BrooksBaseball for the data used in this post.