The bullpen’s heroics have kept the Astros in contention, but the lopsided workload is unsustainable

Entering the postseason, the Astros bullpen was rightly labeled the club’s x-factor. The relief staff’s struggles were endlessly written about during the regular season, and even after additions were made to it at the trade deadline, it was difficult to instill confidence in a reliably inconsistent collection of relievers. But now, what used to be the Achilles’ heel of the Astros has unexpectedly evolved into an indispensable unit the club cannot do without. Providing 7 ²⁄₃ scoreless innings in a must-win playoff game warrants such praise.

Game 4 may as well have been do-or-die for the Astros. Despite being one of a handful of teams to ever force a Game 7 after going down 3-0 in a playoff series — in last year’s American League Championship Series — Tuesday night’s comeback victory staved off a 3-to-1 series deficit. The Red Sox did not beat the Astros in Game 2 and Game 3, they thoroughly embarrassed the AL West champions, outscoring them by a combined 13 runs in both contests. Losing three straight in devastating fashion could have created a hole too deep to get out of.

But thanks to a Herculean effort from the relief corps in last night’s 9-2 win, such a scenario does not exist. With the series now even, the focus of the Astros pitching staff shifts from the viability of their bullpen to the endurance of it. Both attributes have been proved in spectacular fashion, but now the latter could soon be pushed to the limit, with today’s scheduled affair completing a stretch of three games in three days in Boston. Astros relievers covered 15 innings over the past two days, and if Framber Valdez fails to provide any length in Game 5, last night’s continuation of what’s been a seemingly never-ending nightmare will likely persist.

To their credit, Boston hitters have displayed a remarkably disciplined two-strike approach, and to be fair to Houston starters, the usually-stellar play in the field behind them has been mostly absent. With that said, they have failed to put away opposing batters. Two of Zack Greinke’s three walks occurred after he opened each plate appearance with the count at one ball and two strikes. José Urquidy quickly got ahead of outfielder Alex Verdugo in Game 3 after a pair of called strikes, but Verdugo then fouled off five pitches in what was ultimately an 11-pitch battle before drawing a two-out walk, a game-altering plate appearance that eventually resulted in a six-run second inning.

This is the ALCS, and the opposing team is completely locked in at the plate. Little mistakes can trigger a snowball effect. Command artists like Greinke and Urquidy issuing free passes greatly contributed to each getting the early yank. Because of their ineffectiveness, the Astros face the possibility of having to empty their bullpen for a third consecutive day in the event that Valdez again pitches poorly, a daunting notion that is fairly realistic given the southpaw’s Game 1 struggles.

Cristian Javier, who has been nothing short of brilliant, will likely be unavailable in Game 5. The same could also be said for Brooks Raley, Phil Maton and Kendall Graveman. Raley threw 16 pitches on Tuesday after tossing 27 on Monday, and though Maton was economical in both of his Boston stints, using him for a third straight day could be impractical. Graveman, who is an inexperienced consecutive-days reliever, won’t exactly be primed for an appearance on Wednesday either following Tuesday night’s 30-pitch outing.

The Astros were not supposed to be overly reliant on what had long been a shaky relief staff. So far, it hasn’t come back to bite them. But even if the pendulum were to swing back, no one can say the Astros’ once-maligned bullpen cost them in October.