With Week 25 now underway, it’s not too early to look ahead to the final week. That means it’s not too early to starting asking, “which of my pitchers could wind up losing a start?”. That’s the question I tackled in my latest piece for Today’s Knuckleball, as we know it’s only a matter of time before more managers start juggling their rotations in anticipation of the postseason.

One of the starters at risk of losing one of two starts is Felix Hernandez. Not long ago, there was no question that Hernandez was a must-start pitcher, but a lack of consistency has made him less of a sure thing. Still, I was surprised by the results of this Twitter poll.

Out of 69 respondents, only five viewed Hernandez as must-start. The majority were willing to use him if he got both scheduled starts, but more than one-third wanted nothing to do with him.

Less than a month ago, Hernandez was 9-4 with a 3.14 ERA, so what has gone so wrong that he doesn’t deserve the benefit of the doubt? Even when he owned that tidy ERA, Hernandez was walking too many batters and not getting enough Ks to make up for it. Since the beginning of September, he has gone from being a little shaky to full-blown scary. Though one of Hernandez’s three outings was a scoreless affair, he has had trouble throwing strikes and getting grounders in each start. Cumulatively, he has a 60 percent strikes-thrown rate, 36 percent ground ball rate, eight strikeouts and eight walks in those 16 innings.

Each of Hernandez’s problems — poor control and vulnerability to hard and frequent contact — are magnified with his changeup. The graph at the top of this post of Hernandez’s month-by-month Iso on his changeup tells the story of one way (an increased rate of extra-base hits) in which these changes have impacted his results. The table below breaks down the components that have contributed to his declining performance — namely, the decreases in his strikes-thrown, ground ball and whiff rates on his changeup in September. All of these data are from Brooks Baseball.


A look at Hernandez’s heatmaps reveals why he is having these problems with his changeup. Hernandez has had success when he locates it down and in within the zone against righties and down and away in the zone versus lefties. As the graphs show, he had been getting more whiffs in that portion of the zone and few extra-base hits when contact was generated.

Lately, he’s been pitching below the zone altogether, and hitters have been laying off. That’s why he’s been getting fewer strikeouts, more walks and less soft contact.

Hernandez seems to know something is amiss, because he is throwing his changeup less, though he is throwing it enough to affect his performance. It’s not clear why Hernandez is having problems locating his changeup in his usual sweet spot, but the results are worrisome enough that it makes sense to avoid him, at least with only one start.

I’m not usually a proponent of using one start as a referendum on whether or not to use a pitcher, but Hernandez has a chance to offer Fantasy owners some reassurance on Wednesday when he faces the Blue Jays. If he continues his recent trends in that start, it may be time to let him go, even with the possibility of a two-start week looming. Even if Hernandez rebounds, I would avoid him if I were concerned that he wouldn’t get to make his second start.