Skill, Not Luck: Hammel Time

The Cubs rotation has been the driving force behind this team all season. As the club got off to a near-historic start, it was powered largely by a pitching staff with historic run prevention rates. There were questions marks, though, about how sustainable this level of performance was given the low .258 BABIP allowed by the starting staff. That number is the best in baseball as is the starters combined 78 percent left on base rate. This has led to this series of pieces analyzing the extent to which luck has been a part of the 2016 Cubs success story. Here is Zack Moser on Jake Arrieta, Jared Wyllys on Jon Lester, and Isaac Bennett on Kyle Hendricks.

Jason Hammel is a unique case in this pitcher by pitcher study of the staff. Hammel had a 2.58 ERA heading into his first July start, but the peripherals painted a darker picture for Hammel’s future. His DRA was over 1.5 runs higher than his sterling ERA at 4.17. His cFIP predicted regression in his future at 107. Hammel’s story was pretty similar to the rest of the staff with struggles in his most recent turns in the rotation. In Hammel’s case it has seen his ERA balloon up to 3.46 after just two more starts. His cFIP climbed along with it to 112.

 The difference with Hammel is that these July swoons have become a trend. Hammel’s pronounced Jason Marquis disease leads us to not just question whether his performance was skill or luck, but whether or not he can reverse the second half collapses that have plagued his career is the larger looming question. The Cubs are quite familiar with the tall right hander at this point, and his seasons have followed a pretty predictable arc.

*Two starts in July so far

Hammel’s struggles since joining the Cubs pretty clearly begin in July. In 2014, Hammel was pitching for the Athletics by July. Hammel had a horrific first month in Oakland, and the A’s skipped one start in August, and Hammel recovered to finish the campaign strong. Last year Hammel injured his hamstring, and never seemed to be able to recover from that. He flirted with occasional success, but he was clearly not the pitcher he was in the first half. This year there is no event to point to explain the problems Jason Hammel has once the Summer solistice passes.

Jason Hammel is primarily a two pitch pitcher, relying very heavily on his fastball and slider combination. He does throw two fastballs, but tends to lean heavier on the four-seamer than the sinker. Hammel does have a curveball and change, but both offerings are thrown less than 10 percent of the time. Looking at his velocity on his pitches during that 3 year span is illuminating.

There are two discernible trends in the velocity charts from 2014-2016. Hammel struggled in the middle part of 2014 and recovered towards the end of the season. As the chart illustrates, the velocity on Hammel’s fastball and slider both dipped in the middle of the season and both climbed to season-high levels as he regained effectiveness at the end of the season. 2015 saw Hammel’s performance decline throughout the season, and what we see is convergence of fastball and slider velocity further along in the season. In 2016 we are starting to see that same convergence again.

The vertical movement chart is as interesting. 2014 was the slider’s drop only increases as the general trend. In 2015 we saw convergence as the fastball and slider moved together in the amount of vertical movement each pitch generated.The patterns indicated here point to slightly different causes of these second-half flops for Hammel. 2014 appears to be a period of dead-arm-like fatigue. Command left Hammel as his stuff was just not as effective. His BABIP spiked in July while he was also walking more batters than any point in the season. In 2015 we just see continual decline. This would fit the pattern of a nagging injury hampering his performance as his two main offerings became more and more similar in velocity and vertical drop.

In 2016 we are again starting to see convergence like in 2015. The last start Hammel made was both a rebound performance from a career-worst four-inning, 10-run debacle in New York on July 1. Hammel struggled early in his outing against the Atlanta Braves, allowing 3 of the first 6 batters to reach while allowing his sixth home run in the month of July. He recovered to retire the next 13 batters, but the chart indicates that Hammel’s success might be more about the quality of opponent. The flattening of his slider only continued with that outing. The exact cause of this problem is hard to tell. Hammel did have to leave the past outing with hand cramping, and perhaps that was an issue he was dealing with as he was unable to spin a tight breaking pitch that drops as effectively as he did earlier in the year. That does not explain the trending towards convergence occurring in the previous starts.

The question remains then, was Hammel’s earlier success this season just good fortune? Balls in play have found their way into being outs at a frequent pace. There are only five qualified starters that have seen their balls in play turn into outs more frequently than Jason Hammel. He also boasts an 80.7 percent left on base rate which rates twelfth-best among qualified starters. There is a fair bit to point to Hammel’s ridiculous start being partially the result of good fortune. The course of the 2016 season might be as much of a statistical correction as it is skill based.

There is little in the batted ball profile to suggest that Hammel should be this much better at suppressing hits with balls hit into play. Increased infield flyball percentage has shown a correlation with having lower BABIP, but Hammel ranks forty-ninth among qualified starters with his 8.1 percent IFFB%. His percentage of soft hits or hard hits don’t offer any other clues as to why Hammel has been able to lower his BABIP to elite levels this season. Hammel ranks forty-ninth in terms of soft hit percentage and only allows the thirty-second lowest amount of hard hit percentage among qualified starters. However, analyzing these rates on a month by basis provides some interesting insights.

The type of contact that Jason Hammel historically allowed was much weaker than the contact he has been allowing recently. His BABIP is declining, though, and was actually not that extreme of an outlier during his dominant stretch the first two months of the seasons. The only positive indicator for June’s low BABIP is the elevated infield fly ball percentage, but if anything BABIP luck might have shielded Hammel’s numbers from declining earlier. Looking at some different numbers continues to paint a picture of skills being the reason for Hammel’s early season success.

Hammel was a better pitcher in April than he has been in July. The only luck that Hammel might have experienced to start the season was some positive sequencing. His left-on-base percentage was a completely unsustainable 92.3 percent during the month of April, but everything else points to Hammel’s success in the early going being based on potentially repeatable skills. A decline in those skills has resulted in the recent performance drop which, despite the results last time out, are not pointing to a 2014-like rebound.

The Cubs and Jason Hammel are certainly motivated to find answers to why these skills are declining right now. The exact cause is beyond my ability to determine at this point in time, but the Cubs and Hammel are certainly working hard to find and address it. The Cubs will need that as Adam Warren’s sparkling outing against the Reds probably had more to do with the Reds than his abilities.

Lead photo courtesy Caylor Arnold—USA Today Sports.