Diaz Injury Exposes the Lack of Depth on the Astros Roster

 On Saturday, Aledmys Diaz was pulled from the game after being hit by a pitch from Blue Jays starter Ross Stripling. Sunday, news came that Diaz was not pulled for precautionary reasons. He had broken his hand. 

Aledmys Díaz fractured his left hand. He’s going to be out a while. Dusty Baker says approximately 6-8 weeks.

— Jake Kaplan (@jakemkaplan) June 6, 2021

This is obviously bad news for the Astros as Diaz was contributing at the plate with a .278/.341/.435 slash line, and on defense with his flexibility--Diaz has played every infield position as well as left and right field this season. 

But it is also a big problem because the Astros are a team without a great deal of depth. 

Aledmys Diaz is taken out of the game on Saturday.

The Astros have the 5th best record  (33-26) and the 3rd best run differential (+69) in the American League. This success is driven by the team's frontline players. They have seven lineup regulars with OPS+'s at 119 or greater. Five of their starting pitchers have ERA+'s of 111 or better. They have top line talent. 

They have also received contributions from players like Diaz, and guys like Chas McCormick who have played well off the bench. They have helped add value to the team.

But the Astros have been hurt in particular by the contributions of guys on the last several spots on the roster. They are not getting contributions from the 18th through 26th man on the active roster. 

The stats show this. I calculated the total bWAR for the 10 best players so far this season on the Astros.1  The table below shows that those 10 guys have produced 15.8 of the Astros 17.5 Win Above Replacement. The 11th through 17th best bWARs on the Astros sum to 4.9.2 But the rest of the guys on the roster have cost the Astros 3.2 wins. The chart also lists the total bWAR for the Astros (17.5). 

I also calculated these numbers for a number of the other American League contenders. You can see that the Astros have the highest combined bWAR for their top 10 guys, leading the Sox--both versions--by nearly a full run. They have even bigger leads over the Rays, As, and Yankees. The Astros also receive the highest contributions from their 11th through 17th best players--4.9 wins; that's a half a win more than the Rays. 

If MLB teams were limited to 17 players, the Astros would have the most wins in the American League by 2 games over the competition.

But a baseball team needs more than 17 players, and that's where other teams are catching up to the Astros. The Astros have recorded -3.2 wins above replacement from those players, ties with the Yankees for the lowest number on this list. 

The Astros are thus top heavy. They get big contributions from the frontline players to make up for the negatives of the last few guys on the roster. Contrast that roster construction with that of the Rays. The Rays receive nearly 2 wins fewer from their top line players, and less from their 2nd tier players than the Astros. But they make up difference because the players at the bottom of  their roster, who cost the Rays only 0.5 wins. 

The Diaz injury only exacerbates the Astros depth problem. Diaz is one of the players in the 11th through 17th group. His 0.9 bWAR this season sits at the moment between Yordan Alvarez (1.0 bWAR) and Ryan Pressly (0.7 bWAR). 

Diaz's plate appearances will likely be take up by either Robel Garcia or Abraham Toro, neither of which is as good of a baseball player as Diaz. Garcia has slashed .154/.214/.154 this season. More relevant I think is the fact that Garcia has only 28 plate appearances this season.  Dusty and the front office do not think it is worth it to invest much playing time in Garcia. Jake Kaplan wrote that the Astros "claimed him on waivers basically to be an optionable bench bat and so Toro could play regularly in Triple A." 

Unfortunately, Toro has not been playing regularly for Sugarland. He was on the injured list and has managed only 28 PAs, slashing .273/.429/.364. The Astros had hoped to get more regular at bats from  Toro because his major league numbers have been poor--with a .175/.261/.311 slash line in 199 big league plate appearances. 

There have been calls for Toro to be called up now that Diaz is on the IL, but based on these stat lines, it is not clear to me which player should get more run. We need to hope that we catch a hot streak from whichever gets PAs to spell the starting infielders.

But the bigger issue here is the lack of depth on the Astros roster. They are a team that is driven by the top-level stars and those stars have come through so far this season. Their broad base of stars is why the Astros entered the 2021 season as favorites in the AL West. But the efforts of those star level players has been dragged down  by the players at the bottom of the roster--even more than the other American League contenders. 

Theoretically, it is a lot easier to solve issues at the bottom of the roster than at the top. If players are playing below replacement level, the solution is to replace them. Regression to the mean may also help the Astros. Take Brooks Raley as an example; he has the Astros worst bWAR, at -1.0.  But his FIP is excellent--at 2.82--and the contact he allows is soft. Over the course of the season, Raley's actual ERA will move toward his FIP, and his bWAR will rise as well. 

But those replacements or regressions need to take place soon to reverse the sharp negative value of the Astros players who neither big stars nor contributors from the next tier of players. Diaz's injury makes it less likely that will happen. 

Get well, Aledmys. We need you. 

1. For the record, these 10 are Correa, Tucker, Greinke, Gurriel, Altuve, L.Garcia, Bregman, Javier, McCullers, and Urquidy. 

2 These players are Alvarez, Diaz, Pressly, Brantley, Valdez (already!), Castro, and McCormick.