"We've been careful with him in what we've done; he played catch yesterday, and he just said it feels pretty good today," Girardi said. "But it's been tender, and we had the doctor look at it. We decided to do an MRI this morning, and that's what he had."
Based on what he knew of Chamberlain's condition, Girardi said he would not have used Chamberlain differently. Girardi also said that Chamberlain would not need any more invasive treatment unless there was a setback.
"He'd been getting treatment on his elbow for a couple weeks, which is not really abnormal for a pitcher to ice after games," Girardi said. "After games at times, he'd be a little bit stiff, and there's days that we stay away from people. But his stuff had been really good and he had pitched really well, which didn't lead us to believe that he really had an issue."
The Yankees' bullpen, already down a key piece with Rafael Soriano on the disabled list, now becomes even more of a patchwork assembly. Chamberlain's move to the DL was one of four roster moves New York made before the second of three games against the Red Sox, all involving relievers.
The trickle down leaves David Robertson to take eighth-inning responsibilities in front of closer Mariano Rivera, and Luis Ayala and Boone Logan likewise will be asked to step up.
Right-hander Hector Noesi was optioned to Triple-A Scranton/Wilkes-Barre because he would have been unavailable for a few days after throwing six innings in relief of an ineffective Freddy Garcia on Tuesday night.
In place of Chamberlain and Noesi came right-handers Amauri Sanit and Jeffrey Marquez. Sanit, 31, made three relief appearances for the Yankees last month -- the last on May 19 -- the longest for 4 2/3 innings.
Marquez, 26, was a supplemental first-round Draft pick of the Yankees in 2004, and he returns to the organization on a waiver claim from the White Sox. He arrived at Yankee Stadium shortly before 6 p.m. ET, having been designated for assignment by Chicago on Sunday. Marquez's contract was purchased by the White Sox on May 30, but he did not appear for them this season.
Marquez's only career Major League appearance came last season with the White Sox, and he had spent this season with Chicago's Triple-A affiliate in Charlotte. He was 3-4 with a 3.97 ERA in nine starts and threw one shutout.
Marquez last pitched for the Yankees in 2008, at Triple-A.
Noesi has allowed three runs in 15 1/3 innings this season, spanning four appearances and two stints with the team.
"He did everything that we could ask of him," Girardi said of Noesi. "His performance was outstanding, especially for a young kid, because he was thrown in some tough situations. ... It really came down to, we needed some arms."