With an off-day coming up on Monday, the Red Sox don't need a fifth starter again until May 20 in Oakland.
At that point, they'll likely recall a pitcher from Pawtucket to serve as a placeholder until David Price is ready to start his season. Brian Johnson, Henry Owens and Hector Velazquez are the top contenders to get that start against the A's.
Price starts a Minor League rehab assignment on Sunday and could be ready to start for Boston by the end of the month, possibly as early as May 24.
Kendrick got his chance to join the rotation following the season-ending left knee injury suffered by knuckleballer Steven Wright. But Kendrick didn't take advantage of the opportunity, going 0-2 with a 12.96 ERA. He was unable to complete five innings in either start.
Against the Brewers on Wednesday, Kendrick gave up 10 hits and six earned runs over 4 1/3 innings.
"This game's about results," Kendrick said. "I mean, you've got to go out there and give the team a chance to win. The last two starts haven't been that. Sometimes it works out, sometimes it doesn't."
The addition of Ross gives the Red Sox a chance to regroup in the bullpen after two abbreviated starts to start the series against the Brewers.