“If you look at the teams that have won the World Series the last few years, they have had good starting pitching or have used their starters,” Yankees relief pitcher Zack Britton said. “I don’t think you can just bullpen your way to a World Series.”

Though, as Britton noted, the rotation has shown signs of improvement. James Paxton has gotten stronger after a summer knee injury and has performed more like the key off-season acquisition he was billed as. After a 5-0 win against the Red Sox on Monday, Paxton (13-6) had a 2.57 E.R.A. and 58 strikeouts since the July 31 trade deadline — when the Yankees failed to add a starting pitcher.

J.A. Happ has a 5.10 E.R.A., but has allowed just three runs over his past three starts, two against the potent offenses of the Red Sox and Oakland Athletics. Masahiro Tanaka has a 3.80 E.R.A. since the trade deadline, even with a few rougher outings in that span.

Traditionally in a five-game playoff series, teams use at least three starting pitchers, and four in the later rounds. Will Severino be in that group? Boone has said Severino will return to the Yankees this month as a starter, but how much his strength has been built by early October remains a question. He was expected to throw more than 60 pitches in his final minor league start this week.

The Yankees are already taking steps to adjust their staff with an eye toward October. When Sabathia returns on Wednesday from his fourth trip to the injured list this season with chronic knee pain, he will start against the Detroit Tigers and be followed by German, who had been the Yankees’ most consistent starting pitcher until he sputtered of late. Boone said he hoped each pitcher would toss two to four innings. He said it was a way to control German’s career-high workload and evaluate him as a relief pitcher, since he could pitch in either capacity in the playoffs.

As far as Sabathia’s postseason role, Boone said all options would be considered. He added, “We want to win, and C.C., as much as anyone, does.”