I was wrong about Sunday, though — the Astros are using traditional starter Framber Valdez to start game 5 today. Not sure how I overlooked that, Valdez started game 1 so he is on normal rest for game 5. Of course, Valdez has starts of 4.1, 2.2, and just 2.0 innings so far this postseason, although due to ineffectiveness rather than any strategic decision. (To be fair, he also has the longest start of the postseason at 8 IP.)
Atlanta would counter with their game 1 starter Charlie Morton if not for that whole “broken leg” thing, so Atlanta will indeed have another bullpen game. Drew Smyly and Tucker Davidson would be obvious candidates to go some length for Atlanta, but a wild card is AJ Minter, normally a short reliever but he did go 3 innings, 42 pitches in a “start” during the 2020 NLCS, and he didn’t pitch in game 4 Saturday night.