The Houston Astros announced Tuesday afternoon that pitcher Lance McCullers was to undergo Tommy John surgery, causing him to miss the entire 2019 season.

Because fate is crueler to pitchers than German fairy tales are to misbehaving children (in some traditions, Santa Claus has sidekicks who actually eat kids), it’s never a surprise to hear of a pitcher going under the knife. It’s true that Tommy John surgeries have a solid success rate, with the majority of pitchers returning to the mound and resuming their careers — mostly where they were left off. The prospect of elbow surgery certainly isn’t as frightening as various shoulder operations, which are sufficiently risky and cruel that none have a pitcher’s name affixed to them. Still, nobody wants to miss a year-plus of their career due to a medical issue. For the Houston Astros, this complicates both their short- and long-term rotation plans.

One of the reasons the Astros were such a dangerous team in 2018 was the depth of the starting rotation. With the additions of both Justin Verlander and then Gerrit Cole in a six-month period, the team had too many starter — something about which nobody in history has ever complained. It gave them the luxury of being able to absorb some nasty surprises. Without the rotation staying healthier than in 2017, the Astros happily used Collin McHugh and Brad Peacock nearly exclusively as relievers, with sexy results.

As you may have guessed, there’s a big “but” in there. McCullers has never been the healthiest pitcher and, even in 2018, was occasionally playing through the dreaded forearm pain that seems to lead to Tommy John surgery a depressingly large percentage of the time. The rotation thins out very fast in Houston, however, with Dallas Keuchel and Charlie Morton both entering free agency this winter. Neither Cole nor Verlander are signed past the 2019 season.

That leaves, by my reckoning, only McCullers and Peacock under contract for 2020 among Astros starting pitchers who are established major leaguers. The injury to McCullers gives the Astros another question past 2019. Even that is more optimistic than the actual scenario, given that Peacock’s never thrown 150 innings in a season before. The good news is that the Astros have Forrest Whitley, arguably the best pitching prospect in baseball, while Josh James looked terrific in the majors at times. If you take pitching prospects as a certainty, however, you’ll regret it depressingly often. What the McCullers injury does is speed up the timeline for Houston to make some decisions, now that losing Cole or Verlander after 2019 may be even more of a problem than it looked like a few weeks ago.