Johan Santana's 2.96 ERA obscures the fact that he is not as good of a pitcher as he used to be.

Is anything wrong with Johan Santana? Some writers were asking the same thing last year at this time, only to see Johan rebound with another excellent second half, culminating in a dominant performance against the Texas Rangers on August 19, giving up two hits over eight innings, while striking out 17 (and walking zero).

However, after this start, Santana struggled during the rest of the season. Over his last 44 innings, he allowed an ERA of 5.11 and struck out "only" 44 (while this is still a lot of strikeouts, it’s down from the 191 strikeouts in his first 175 innings). This could be read as a bump in the road – perhaps Johan was tired, perhaps it was the result of a small sample size fluke.

This season, some people have once again wondered if anything is wrong with Johan. His "problems" have been attributed to some combination of poor run support/overrating win-loss record, and the fact that Johan has always been an excellent second-half pitcher (except for last September). If we examine Johan’s statistics more closely, we see there is indeed cause for concern, despite his pristine 2.96 ERA.

First of all, Johan’s strikeouts are still "down." While 109 strikeouts in 121 innings is nothing to sneeze at, it’s well down from Johan’s rate over the last several seasons (the last time Johan struck out less than a batter an inning was way back in 2001). This is even more troublesome given the fact that Johan is now pitching in the National League, and thus gets to face the pitcher (or a pinch hitter) three or four times a game, as well as generally weaker competition (as evidenced by the American League’s domination in interleague play).

Additionally, Santana’s walk rate is up (albeit slightly). He has walked 2.38 per nine this season, after walking 2.14, 1.81, and 1.75 per nine in each of the last three seasons, respectively. This is not a huge jump, but considering the drop in strikeouts and move to the easier league, it is not a particularly good sign for Santana.

Perhaps of more concern is Santana’s velocity, which is down. This season, according to Fangraphs, his average fastball velocity is 91.2 MPH. Last year his fastball averaged 91.7, and in the previous two seasons it averaged 93.1 and 92.4 MPH. Interestingly, Santana’s changeup velocity has also decreased from 81.9 and 81.8 MPH over the previous two seasons, to 79.9 MPH this season. Additionally, the velocity of Johan’s slider is down, and he is using it less frequently than in the past.

This year, Santana’s slider averages 83.4 MPH. It was 84.9 MPH in each of the past two years, and his career average slider is 84.4 MPH. Interestingly, Santana has been using his slider less often this year than previous seasons: this year, 12.8% of his pitches have been sliders. In his career, 14.6% of his pitches have been sliders, and back in 2005 and 2006 he threw 16.9% and 16.5% sliders (he used his slider less frequently last year as well, using it only 11.6% of the time).

Additionally, Santana has been using his slider less often when he is ahead in the count this season than he did last season. Here is a chart detailing the percentage of times he has thrown each of his three pitches when the count has been 0-1, 0-2, and 1-2.

Santana is throwing the same amount of fastballs when he is ahead in the count, but he has sacrificed his slider in favor of his changeup. And his strikeouts are down. Is this a coincidence? It could be. But, given Santana’s dominance over the last six years, it’s surprising that he is choosing to throw fewer sliders when ahead in the count this year.

Santana is also throwing fewer first pitch strikes this year – 60% of his first pitches have been strikes. He had not delivered a first pitch strike less than 64% of the time since 2002. Additionally, in the past if Johan delivered a first pitch strike, the batter had very little chance of getting a hit in that at bat. From 2005-2007, opposing batters hit .187/.215/.315 in all at bats that had an 0-1 count, and struck out 36% of the time. This year, however, batters are hitting .221/.264/.359 in all at bats that had an 0-1 count, and have struck out 32% of the time.

In other words, Santana has earned 0-1 counts less than in the past, and even when he does get the count to 0-1, he has given up more hits and struck out fewer batters in those at bats this season than in the past."

Simply put, Santana’s stuff does not seem to be as good as it used to be. Take a look at this table:

This season, Santana is getting called third strikes at the same rate as before, but is getting far fewer swinging third strikes; as a result, a significantly higher percentage of his strikeouts have been called third strikes, rather than swinging strikes. Batters are making contact when they swing more often than in the past. Santana is also working himself into 0-2 counts less often than in the past.

And remember, even when he manages to throw strike one (which he has done less often this year than in the past), he’s not as lights-out as he used to be, as he strikes out fewer hitters and allows more hits after an 0-1 count than he has in the past. 

To summarize: Santana is not throwing as hard as he used to – the velocity of his fastball, changeup, and slider are all down. He is throwing his slider less often when he is ahead in the count than he used to. Additionally, Santana is throwing fewer first pitch strikes and is less dominant in the at bats in which he does throw a first pitch strike. He is getting himself into 0-2 counts less than he used to. He is walking more and striking out fewer hitters (despite pitching in the National League), and a higher percentage of the strikeouts he does get are called third strikes, rather than swinging strikes. In fact, batters are making contact more often when they do swing than ever before.

Don’t get me wrong: Johan is still very good. However, this season he has not been the same pitcher that he had been throughout most of his career. The Mets can only hope that this downgrade is a bump in the road and not the beginning of a trend.