Buchholz, 29, has been dealing with fatigue in his shoulder for much of the postseason, and has been questionable this entire series. He did eventually get a start in Game 4, but lasted just four innings and topped out at 89 miles per hour with his fastball, well below his normal velocity.
The right-hander was effective in his short outing on Sunday, however -- holding the Cardinals to one run on three hits -- and said after the start that he felt stronger than expected, so perhaps there is more to it than what the radar gun spits out.
Buchholz has made just two relief appearances in his seven seasons with Boston, the last of which came all the way back in 2008. Nothing of value can really be culled from a sample of four innings, so there's no telling how he'll fare in a relief situation Wednesday.
John Lackey will get the start for the Red Sox on Wednesday. If he's able to get into the seventh inning like he did in Game 2, perhaps Buchholz will be used to bridge the gap between the starter and closer Koji Uehara. Lackey was used in a similar capacity in Game 4.