Jeremy Hazelbaker's season has been a fun one. That's because it's special any time a 28 year old with over 3,000 Minor League plate appearances and zero MLB plate appearances has one of the best debuts in MLB history, even if he was over-shadowed by the best debut of all time by a guy on his own team the same year. For the first month of the year, Hazelbaker was hitting everything a long way, but he's cooled off a bit in May. As May comes to a close, let's look at Jeremy's April/May split:
Woof. April was fun of course, but the strike outs and walks combination were a bit troubling even then. In May those strike out and walk numbers became horrific. At the time of me writing this (yesterday), he's had 48 PA in May. 302 players had at least 40 PA so far in May, and of those, Hazelbaker had the 3rd worst K-BB%. That's the worst 1%. Strike outs and walks are just two parts of a hitters profile, and strike outs are probably the least important, but when a player performs extremely bad at both strike outs and walks, he creates such a substantial hole that exceptional contact quality is necessary to make up for it. We went through this with Randal Grichuk last year, and this year he has improved those numbers.
While we're just talking about 48 plate appearances here, as the split above shows, the strike out and walk numbers were already uncomfortably high. Going into yesterday's game he held a 32.8 K% and 5.7% BB%, resulting in a 27.1% K-BB%, the 6th out of 238 among players with at least 120 PA (Jeremy has taken 122 PA). That's the worst 2.5%. Even though Pham was projected as better going forward, when he returned from injury he was assigned to Triple-A in lieu of Jeremy, on the basis of Hazelbaker's short sample size success. And I actually supported it: baseball players are people too, and when a person does everything asked of him and much more, they're not going to handle a demotion very well. As long as he continued to produce, he'd continue to hold a roster spot.
Well, he hasn't continued to produce, and now the question turns back to who is projected to be better going forward. I referenced my post on Grichuk a few paragraphs up, here's a chart from that post:
From 2012 to 2015, I grouped each player season with more than 350 PA in buckets based on their K-BB%. Group 1 had a K-BB% of less than zero, meaning they had more walks than strike outs. Group 2 had a K-BB% between 0% and 3%, Group 3 had between 3% and 6%, and so on, up to group 11 which had a K-BB% of more than 27%. For those groups I was then able to create averages for each group for the stats above. The two groups featured above show the group Grichuk fell into in 2015 (24%-27%, group 10) and the group Grichuk has been part of in 2016 (12%-15%, group 6). If we shave a few tenths of a percentage point off of Hazelbaker's K-BB%, then he falls into the tenth group, and the 6th group is the group that Tommy Pham fell into in 2015.
As you can see, a 24 point increase in ISO and a 15 point increase in BABIP only gets Hazelbaker's group within 8 points of Pham's group in wRC+. But as I mentioned that's not even Hazelbaker's real group, as after his pinch-hit strike out on Sunday he actually now has a 27.1% K-BB%. There's only been five player seasons over 350 plate appearances in the last three years that have exceeded a 27% K-BB%, here's each of them:
Not a pretty list at all. These are the only seasons from 2012 to 2015 that are longer than 350 PA and had a worse K-BB% than Hazelbaker has had so far this season. These players needed to perform very strong in ISO and/or BABIP just to get to the "below average but playable" category. I can't imagine how bad Zunino's backup must have been in 2015, or at least I hope he was really bad otherwise he should have been playing more. Unfortunately for Jeremy, Tommy has some impressive batted ball results as well, and is projected well going forward. Here's how Hazelbaker has performed in BABIP and ISO in 2016, and how Pham performed in 2015, as well as how both are projected going forward by an averaged Rest-of-season (ROS) projection of Steamer and Zips:
Hazelbaker has displayed more power in his short sample size in the league than Pham has in his short sample size, but that's about it. As far as the projections are concerned, Pham and Hazelbaker are at a virtual tie in ISO, with Pham projected as better in terms of BABIP. Hazelbaker needs to be worlds better than Pham in contact quality, and he might not even be better at all.
With this analysis, it's hard to argue that Hazelbaker is a better hitter than Pham. Hazelbaker has had some good results on contact, but so does Pham, and Pham has been by far better in terms of strike outs and walks. Not only is Pham better, but the argument is strengthened by the handedness of the players involved. As a right-handed hitter, Pham is of more use on the current roster than Hazelbaker. Despite all the depth the Cardinals have accumulated, Matt Adams and Brandon Moss have still taken 17% and 24% of their plate appearances vs. left-handed pitchers respectively. A big part of that is the fact that Hazelbaker, the main alternative to either of those two, is also left-handed. Swapping out Pham for Hazelbaker would give Matheny the ability to better hide those lefties from same-handed pitching. Being that they both otherwise play center-field and can serve well as Matt Holliday's personal late-inning defensive replacement/pinch runner, there's no real reason to prefer Hazelbaker on the roster over Pham.
With that said, I'd expect to see Hazelbaker again. For one, Pham gets injured a lot. Hazelbaker would probably be the next man called up in the event that any of the outfielders or first basemen get hurt. Next year, with Brandon Moss departing, Hazelbaker would have the leg up on a presumed 5th outfielder competition. Hazelbaker is and will continue to be a nice org piece. It's just that in this case, Tommy Pham is the better player, and the better fit for this roster.