How were the Red Sox able to replace Steven Wright on their ALDS roster?

The Boston Red Sox replaced Steven Wright on their American League Division Series roster against the New York Yankees in between Game 1 and Game 2, after the relief pitcher suffered a left knee injury and was unavailable for the opener.

“I know he’s down. It sucks for him, but we have to move on. We have a game tonight. And we have Heath now,” Red Sox manager Alex Cora said Saturday. “We know how we’re going to use him. We’ll turn the page and try to win tonight.”

Heath Hembree is the roster replacement for Wright. The right-hander had a 4.20 ERA in 67 games for the Red Sox, with 76 strikeouts and 27 walks in 60 innings.

But how was this change able to happen in the middle of a series, and just one day after the 25-man Division Series rosters were finalized?

Any sort of mid-series roster change has to be approved by Major League Baseball. In this case the diagnosis was reviewed by Dr. Gary Green, MLB’s medical director, who also reviewed Wright’s medical history, a history that included left knee surgery in May 2017 that wiped out last season after only five appearances.

As part of major league rule 40(A), any injured player who is replaced must have his roster spot taken by someone of their ilk. In other words, pitchers must replace pitchers, and position players must replace position players.

There is a penalty for replacing someone on a roster in the middle of a series, namely that said player is ineligible for not only the remainder of the current playoff round but for the next round as well.

Wright wouldn’t be eligible for the American League Championship Series should the Red Sox advance, but if Boston were to make the World Series he could rejoin the roster by then. The official wording of rule 40(A)(4)(C):

The injured player being replaced shall be ineligible to play for the remainder of such series, as well as the next subsequent post-season series that year. Notwithstanding the foregoing, a replaced player, who has suffered an acute concussion during a post-season series, may be eligible to play in the next subsequent post-season series that year, provided that the player has been ineligible to play for a minimum of seven days, and Major League Baseball’s Medical Director has reviewed a Return to Play form and supporting information and approved the reinstatement.

Losing Wright for another series might be a moot penalty anyway since he might not be ready by then anyway. But for other injuries it could be relevant. Yankees outfielder Aaron Hicks, for instance, injured his hamstring and was held out of the Game 2 lineup. If Hicks had to miss a week or two, replacing him on the roster might have been an option, with the hope he would be ready for the World Series — again, if New York in this case advanced that far.

But Hicks’ MRI came back clean, so the Yankees don’t need to worry about replacing him on the roster. In fact, even though he’s not starting, Hicks is available off the bench on Sunday night.

“Aaron will be hot tonight and I wouldn’t hesitate to use him in a big spot, if the situation comes up,” Yankees manager Aaron Boone told reporters on Saturday.