When you have an underachieving hitter, you have one of two options, you either continue to start him and hope he turns around soon or you bench him for a presumably better option. After a week of strikeouts from Giancarlo Stanton I began benching him until I saw signs of life. Now he appears to be fine. With pitchers you obviously have the same options but the thought process is a little different. For one thing, you have a lot less of them. Secondly, a common strategy is to draft only one ace with the expectation that he’ll ground your staff’s ratios. But what if it’s your ace who’s struggling? For every Zack Greinke who bounces back for good, there’s a Matt Harvey who alternates awesome starts with getting shellacked by the Braves.

Jordan Zimmermann was not a pitcher that I was particularly high on coming into 2016. It was common knowledge that he had a declining strikeout rate that was never particularly good to begin with. However, he impressed right out of the gate as he was unscored upon in his first three starts with the Tigers. He ended April with a .55 ERA and 5-0 record. I was beginning to think that “Jeff” had not been so crazy when he offered Zimmermann to me for Xander Bogaerts. Of course it took me exactly zero seconds to decline the deal and I obviously haven’t regretted it.

But then May 1 came and went. Zimmermann began to show signs of weakness. After a few quality starts to begin the month everything went haywire culminating in Friday’s three inning seven run affair which left his ERA at a less than sightly 3.81. The main culprit to Zimmermann’s decline has been a pathetic strikeout rate of 5.96, ranking 90th out of 97 pitchers with qualifying innings. A strikeout is the single best thing a pitcher can do that he has a decent amount of control over and Zimmerman has been one of the worst pitchers in baseball at it. Even worse, his strikeout rate for June has dropped to major league worst 4.97 per nine innings. Only Martin Perez would be jealous of that rate.

Three things stick out as factors in Zimmerman’s lack of success. First, the rates at which batters swing at pitches out of the strike zone have dropped by about 25 percent on his fastball and cut-fastball. His slider still appears to miss bats. Secondly, the rate at which batters swing and miss at his cut-fastball has been cut nearly in half from 12.1 percent to 6.3 percent. Lastly, his velocity has dropped by about a mile per hour, down about two miles per hour from his career year in 2014.

Nothing else really seems to be out of the ordinary for Zimmermann, he’s not been particularly unlucky and other than the swing and swing-and-miss rates on his cut-fastball, his profile hasn’t really changed. He just didn’t ever have much room for err and he now has none. I would expect that he’ll make an adjustment that results in better outcomes on his bread-and-butter pitch, the cut-fastball, but even if he does, is it really worth it for a six strikeout per nine guy? I would say it’s not.

A pitcher headed the opposite direction is Trevor Bauer. I had long been one of his biggest apologists, citing how good his pitch selection and quality appeared. The problem was threefold: he threw way too many balls, walked way too many hitters, and got crushed at times up in the zone. When he was demoted to the bullpen earlier this year, I had seen enough. And at first he didn’t give me much reason for regret as he struggled in middle relief. But then something clicked. Since June 6th he’s been absolutely dominant. His old bugaboo the base-on-ball has been under control and the strikes have been plentiful. More importantly to fantasy owners, the results have matched the stuff as he hasn’t allowed more than two runs from that starting point.

With a pitcher as talented as Bauer, the chance of a massive payoff makes an investment worthwhile. To determine the amount of the investment, I took a look at the underlying inputs. The first thing that stood out to me was the spike in ground ball rate. After never having a rate above 40 percent, Bauer is now inducing ground balls at a 49 percent clip. It’s not due to pitch location either. As you can see below, there’s really not a change in where his pitches end up other than the fact that more of them are in the strike zone.

The most significant change I could find was in his pitch selection. Gone are the days of relying on the four-seam fastball and in its place is a two-seamer.

Considering that a conscious and sustainable change has been made in Bauer’s approach to hitters, I feel very confident that he will finally realize his potential as a frontline starter. His velocity is actually up a tick to 95-96 miles per hour and he has finally capitalized on the ability that led so many people to expect so much from him.