Last night in Chicago Jake Arrieta had one of his worst games of the season going 6.1 innings and giving up 6 earned runs on 5 hits and 3 walks. It was, to most, somewhat of a surprise as he was coming off one of his best starts on August 23rd where he pitched 8 scoreless innings of 2 hit ball at San Diego. If you look at his overall line for the year you probably would not be too concerned as he has a 2.84 ERA, 1.048 WHIP with 16 wins on the season. I would argue though that there should be some concern.
It would be unfair to just say Arrieta is struggling because his season hasn’t been what it was in 2015, since that was an amazing season for him and he was the Cy Young winner in the National League. My concerns are more rooted in numbers that not everyone likely pays attention to.
Over Arrieta’s best two seasons of his career, so far, 2014 and 2015 he had a 2.08 ERA and a 0.915 WHP. He obviously isn’t living up to that, but ok we can’t expect that necessarily. In that same span of time he had a 2.31 FIP, 0.4 HR/9, 2.1 BB/9 and 9.4 K/9, this is where my concern falls. In 2016 his FIP is 1.16 higher at 3.47, his HR/9 has nearly doubled to 0.7, BB/9 is up to 3.5 and he is not striking batter out at the same clip with an 8.6 K/9. His struggles are very prominent in his last 11 starts where he has a 4.20 ERA, 34 walks and only 60 strikeouts in 75 innings. To make matters worse he has a record of 6-6 in those games.
So what is wrong with Jake Arrieta? According to BrooksBaseball.net it wouldn’t appear that he is injured as his velocity is right in line with his 2015 numbers. His pitch mix does appear to have changed. As you can see from the chart below he has begun to rely more heavily on his hard stuff versus his breaking pitches, throwing his fastballs 14% more of the time then he did in 2014 and 2015. As the 2016 season has progressed that has become an even bigger trend as he has thrown hard pitches 73.21% of the time in the month of August.
My theory, however, is more than that. Last season Arrieta threw a career high 229.0 innings, 55.7 more innings than his previous high of 173.3 set in 2010. Since 2010 he has thrown 119.3 in 2011, 170.7 in 2012, 154.7 in 2013 and 176 innings in 2014. It is not that a jump to 229 innings is a death sentence for a pitcher, but that is a fairly large workload and many of those innings were in higher pressure situations than ever before. It is very likely with Arrieta already at 168.0 innings in 2016 that he is just wearing down from last year’s innings and because of that his stuff just isn’t as crisp.
Though we don’t know for sure what is wrong with Arrieta, what we do know is the Cubs have to find a way to get him back to his high end form soon as they are likely in the playoffs for 2016 and have a good shot of making it to the World Series if they can get him right.