Pat Holden wrote before the season started that the Orioles needed to put Kevin Gausman in the rotation because he was one of the Orioles' top five starters. The Orioles’ rotation has struggled with consistency this year as only Gonzo, Jimenez, and Chen have performed well and therefore the Orioles are hoping that Gausman can help strengthen the rotation. It makes sense to look at his statistics to see whether he is likely to fulfill that role.
As a starter from 2014-2015, 70.1% of the pitches that Gausman threw were fastballs. This was the 7th highest percentage out of 169 starters that pitched at least 100 innings over that time frame. It’s possible to be a successful starter while throwing such a large percentage of fastballs and indeed pitchers like Lance Lynn and Shelby Miller threw a larger percentage of fastballs while still being successful. This first chart (using data from ESPN's stat and information portal) shows the percentage of pitches that Gausman threw in 2014-2015 against batters based on whether they’re left-handed or right-handed and based on whether there are runners on base.
Gausman doesn’t throw a splitter but rather a changeup that acts like a splitter. For the sake of simplicity, I’ll refer to it as a splitter in this article. He primarily throws his fastball and splitter against left-handed batters while occasionally throwing in his changeup and slider. He rarely uses his slider against left-handed batters especially when men are on base, possibly suggesting that he lacks confidence in the pitch against lefties. He primarily uses his fastball against right-handed batters but uses his splitter and slider with the same frequency as secondary pitches. This next table shows how successful he has been using these pitches against left-handed batters.
So far, Gausman has had poor results with his fastball against left-handed batters with the bases empty but has been more successful with men on base. This could hint at either a mechanical problem or could simply be nothing more than luck. However, opposing left-handed batters have hit his fastball at a .293/.371/.457 line suggesting that left-handed batters are able to crush his fastball. Opposing batters are also able to crush his slider as they average a .500/.500/.500 line against it. Limited data suggests that he is less effective with the bases empty than with men on base.
His split-change has been devastating against left-handed batters. Most are unable to hit it in any circumstances and opposing batters have put up a line of only .176/.222/.230. His normal change-up has also been hard for left-handed batters to hit as they average only a .250/.250/.250 line against it. Limited data suggests that he is less effective with this pitch with the bases empty than with men on base. This next chart explains why Gausman has been effective or ineffective with each of his pitches against left-handed batters.
Opposing left-handed batters swing at fewer fastballs when the bases are empty than when men are on base and this has resulted in an large increase in called balls but a minimal increase in called strikes. In addition, opposing batters are less likely to miss his fastball when the bases are empty than when they’re on base. It’s as if these batters are able to better read when his fastball will be a ball or a strike in those situations and therefore they have better results. This could be just random variation but it looks like something worth noting.
Gausman’s split-change has resulted in a considerable amount of swinging strikes by left-handed opponents despite the fact that it’s rarely thrown in the strike zone. This gives him a pitch that he can go to when he has two strikes on a left-handed batter and needs to get a strikeout. This pitch also seems to be more effective with men on base than not but Gausman has benefited from a high foul ball rate when the bases are empty.
Gausman primarily throws his slider in the strike zone and therefore is able to pick up a large percentage of called strikes. Unfortunately, most sliders are designed to rarely be in the strike zone and as a result it probably isn’t surprising that opposing batters are able to crush it when they do make contact.
Most of Gausman’s regular change-ups against lefties end up being called balls. In an extremely limited sample, batters often don’t miss when swinging at his change-up when the bases are empty but have had difficulty when men are on base.
The data seem to indicate that Gausman struggles when pitching to left-handed batters when the bases are empty. This could either be due to small sample size or could mean he has a mechanical problem when pitching in the windup. In any event, the results when left-handed batters hit his fastball are below-average and for his slider is awful. His split-changeup is a very good pitch but isn’t designed to be thrown for a strike. In order to be successful against left-handed hitters, Gausman needs to figure out how to upgrade his fastball.
This next chart shows how Gausman has performed against right-handed batters.
Gausman’s fastball is very good against right-handed batters when the bases are empty but gets hit hard when runners are in scoring position. He has shown an ability to use his splitter in order to get strikeouts but has struggled when opponents have been able to make contact probably due to small sample size. Right-handed batters have struggled to hit his slider when there have been runs in scoring position but they have crushed it in every other situation. This next chart shows how right-hand batters have hit his pitches.
Right-handed batters are usually able to make contact with Gausman’s fastball. What is interesting is that his fastball is more likely to result in a called strike when the bases are empty than when runners are in scoring position. It appears that batters are swinging at strikes more in those situations and that could be why right-handed batters are doing better with runners in scoring position than when the bases are empty.
In a limited sample, right-handed batters have mainly simply been unable to make contact with Gausman’s split-change when runners are in scoring position. They’ve put only two of his 80 splitters with a man on base into play. Likewise, they’ve only put four of his 59 splitters with the bases empty into play. He may not throw his splitter often against right-handed batters but they struggle to hit it when he does.
Gausman throws his slider for strikes way too often when the bases are empty and as a result it causes a lot of called strikes and gets pounded when batters do swing. Interestingly, he doesn’t throw his slider for strikes as often when there are runners in scoring position. He gets fewer called strikes with the pitch in that situation but also causes batters to miss considerably more often and doesn’t get pounded when batters do make contact. This indicates that his slider is an effective pitch in certain circumstances and may become more effective with further practice.
The data suggest that Gausman has a number of weaknesses that he needs to address before he can truly realize his potential. He does have an excellent split-changeup but his slider is terrible. It’s hard to be a starter with only two pitches. Shelby Miller is able to be successful throwing the fastball 70% of the time but he has two dominant other pitches that he can throw while Gausman only has one.
The problem is that Gausman thinks that he can be successful with just using his fastball and split-change against left-handed batters while using his slider solely and rarely against right-handed batters. The Orioles have discussed having Gausman throw a curveball, but ESPN's portal suggests that he didn't throw a single curveball in 2015 in the majors. As Buck said in the article, "Kevin’s leap is going to be if he can command the secondary stuff. He’s not going to sit out there and throw 96-mph fastballs by major league hitters if that’s all he can do."
Realistically, he either needs a much improved fastball (probably not likely) or he needs to figure out how to throw a slider or a different third pitch. Until he learns that, he’ll be able to be a decent starter but will never be able to reach his potential role as an ace.