The Astros Bullpen: Better Than You Think, But Not As Good as You Hope

Seattle is one of my favorite cities, and that fact, combined with the mediocrity of the Mariners franchise over the last decade, makes it hard to imagine having a bad weekend in America's Emerald City.  And yet, here we are.

In the crosshairs of the team's beat reporters and Twitter followers is the bullpen. On Friday night, five relievers combined to give up 4 runs and to blow a 3 run lead. On Sunday, a disastrous 5th inning, highlighted by a 2 run homer given up by Brooks Raley to the first batter he faced turned the ballgame to the Mariners advantage. The Astros managed to avoid a bullpen blowup on Saturday night primarily by not using it--starter Zack Greinke went 8 strong innings before Ryan Pressly earned his first save of the season.
I add here to the #Discourse around the Astros bullpen.  But I hope not to add to the "sky if falling; I'm gonna call sports talk radio about it" sense that is percolating throughout the fanbase. My take is is more subtle, if more complicated than what is being expressed in 280 characters. 
I make five arguments about the Astros bullpen:

1. It has not been as bad as many fans perceive it, 
2. The bullpen is still performing at a below average level
3. That level is meeting pre-season projections, if not expectations;
4. There is reason to believe the bullpen could improve as the season goes on, and
5. Even with improvement, the bullpen will still be a liability. 

I'll take each of these in order.

The bullpen  has not been as bad as many fans perceive it

Where does the Astros bullpen rank among their colleagues in other major league pens?  I think many Astro fans would say at the bottom. The poor performance in Seattle brought the typical calls for trades and wholesale changes among those with quick trigger fingers.

The table above shows the statistics and major league rank of the Astros bullpen so far in 2021. The ranks show the usual bumps and wiggles of data, but in general, they show the Astros bullpen has been in the third quartile of Major League Baseball this season.  They are not good, but they are not the horror show that has been declared by many fans. 

The Astros bullpen has its highest rank in batting average against. Their .219 mark is 14th in the majors (all stats current as of Monday morning). The lowest is in Win Probability Added (WPA); Astro relievers have reduced the team's win probability by nearly a whole win through the season's first two-and-a-half weeks. The low performance here indicates the bullpen is performing worse in high leverage situations (and thus, the outrage of Astros fans has a rational basis).  

The bullpen is still performing at a below average level

Of course, the third quartile is below the midpoint for major league teams. The Astros have playoff expectations, and below average components of the team do not help a team get to the playoffs. 

The Astros have received good pitching from Ryan Pressly so far; he has not allowed a run in 6 IP, striking out 6 while walking only 1. But where the Astros have been lacking in particular is in the ability to get the ball to Pressly with a lead. Middle relief has faltered (especially on Friday night), and the only reliever with a FIP under 3.50 other than Pressly is Brandon Bielak, whose perfect 4 2/3 IP in Oakland on opening weekend was impressive and is helping those numbers.
Particularly worrisome has been the pitching of Joe Smith, who was expected to be one of the key set-up men for Pressly this season. Smith has given up 14 hits and 7 runs in 4 1/3 IP.  And as Jake Kaplan noted, "the average velocities of [Smith's] sinker and slider are down 2-3 mph from 2019." 

That level is meeting pre-season projections, if not expectations

Fangraphs projected the Astros bullpen as 23rd in MLB

What did we expect from the bullpen this season?  This off-season, the Astros signed three free agents from other major league rosters. Of those, two were in the bullpen--Pedro Baez and Ryne Stanek. The front office made few moves this off season to improve the team, but the bullpen was one of their priorities.

Yet despite those moves, statistical projections were pessimistic about the Astros bullpen. Fangraphs does a "Positional Power Rankings" series based on their Depth Charts fWAR projections for each player. They ranked the Astros bullpen as 23rd in MLB entering the season. In short, they expected the Astros bullpen to be in the third-quartile of MLB, which is where they have ended up after the first 15 games of the season. 
Fangraphs projected the Astros bullpen as a whole to have a 4.29 ERA, a 4.49 FIP, a 9.4 K/9, and a 4.1 BB/9. If you look at the chart above, you can see that the bullpen is performing very closely to all of those projections. We should have expected this. 
The Positional Power Rankings article concludes it's Astros section by saying "If we anticipate Pressly will hold serve and Parades and [Bryan] Abreu take a step forward, then this will be an average bullpen. It will take one or more of the big question marks to come through for it to be more." No one has taken a step forward, so this is a below average bullpen. 
The bullpen could improve as the season goes on
Yet, there is good reason for optimism over the long term for the bullpen. At the moments, six members of the Astros bullpen are on the injured list--Pedro Baez, Josh James, Austin Pruitt, Enoli Parades, Andre Scrubb, and Blake Taylor. 

Recent reports indicate that Scrubb could be activated "during the upcoming homestand" and that Paredes and Baez have resumed throwing, though Baez is "still a ways off" according to Dusty Baker. James, who had hip surgery in the off-season is not expected back until late May or early June. Pruitt is on the 60 day IL and is not eligible to return until early June.  Taylor went on the IL Saturday, and there is not a timetable for him. 
A healthier bullpen would be a better bullpen, especially if Baez can make his debut and fulfill the role intended for him when the Astros signed him.
The ultimate rosy scenario for the Astros bullpen would be a return to the active roster for Framber Valdez combined with the rest of the rotation staying healthy and off the IL. This would allow Cristian Javier to join the bullpen as a multi-inning weapon. I think that is his best role long term. 
I should note that this scenario is unlikely to come to fruition--it is hard for a team to maintain the health of its starting rotation over the long haul of a baseball season. But if everything breaks right...

Even with improvement, the bullpen will still be a liability. 

A return to health from relievers like Baez, Paredes, and James would certainly help the bullpen. But none of them have a track record of being lights out relievers who will shut down the top lineups. They are average to above average relievers. That would be better than what we have seen so far. But look to the Fangraphs projections. They did not see this as a strong bullpen, and they argued that if players stepped up, the bullpen could be average.

An average bullpen would be an improvement over what we have seen from Astros relievers, especially in Seattle this past weekend.  We need to be prepared to watch the bullpen blow up more than we would like.  The bullpen is not performing as bad as perceptions, but are unlikely to improve enough to meet our expectations. 

This team needs the offense to produce to win games. Fortunately on that front, help and improvement are definitely on the way.