FORT MYERS, Fla. -- Let there be no ambiguity about the injury that will force Tyler Thornburg to open the season on the disabled list. Tests administered Tuesday showed the Boston Red Sox reliever has an impingement of his right shoulder.
There is, however, plenty of uncertainty over what might have caused the problem.
In relaying the diagnosis to reporters before Tuesday night's game against the Pittsburgh Pirates, Red Sox manager John Farrell said it's "a lot false and very shortsighted" to pin the injury on the team's shoulder strengthening program, which Thornburg found to be exhaustive after being acquired in a December trade with the Milwaukee Brewers.
But in a March 11 interview with ESPN.com, Thornburg explained that the volume of shoulder exercises required by the Red Sox combined with the usual bullpen sessions and throwing of live batting practice early in camp "started to weaken those muscles a little bit." Thornburg said his conditioning program with the Brewers consisted of only a handful of exercises. The Red Sox's regimen, which Thornburg said he didn't see until January, is considerably more intense.
"I saw the big list of a ton of exercises and I'm thinking, 'OK, those are all the exercises that they can run through,' and it was like, 'No, this is our shoulder program for the day,'" Thornburg said. "That part was kind of different. The first time doing it, just kept doing another exercise, another exercise, I'm thinking, 'This is a lot.'"
The Red Sox shut down Thornburg after a March 1 appearance against the Baltimore Orioles in which he allowed three runs on three hits and a walk and recorded only two outs. He threw 20 pitches in a minor league game last Friday and was scheduled to pitch Monday against the Orioles before being scratched with spasms in his upper right trapezius.
Thornburg isn't expected to throw for a period of 10 days before being re-evaluated.
Farrell chalked up Thornburg's injury to overall "shoulder fatigue" and said Thornburg was shut down initially because of inflammation in his shoulder. Farrell also said it's "not uncommon" for a player to overexert himself in spring training in order to impress a new team, though he couldn't say if that was the case with Thornburg.
But Farrell defended the Red Sox's shoulder program, which earlier this month he described as "maybe a little more in-depth" and features exercises that "are maybe not administered elsewhere."
"Any time a player, and we've had a number of players come in, when you come into a new organization, there's a period where guys adapt," Farrell said. "Could it have been different from what he's done in the past? Sure. But to say it's the root cause, that's a little false. That's a lot false -- and very shortsighted."
Thornburg, expected to pitch the eighth inning for the Red Sox, was acquired for infielder Travis Shaw and two minor leaguers. The Red Sox opted to trade for Thornburg rather than attempt to re-sign 42-year-old setup man Koji Uehara.
Recovery times differ depending on the pitcher and the degree of the injury, but to gauge a potential timetable for Thornburg, it's worth noting that Red Sox reliever Junichi Tazawa missed 18 days last season with a shoulder impingement. Right-hander Joe Kelly was a starter earlier last season when he missed a month with a shoulder impingement.
On Monday, Red Sox president of baseball operations Dave Dombrowski said he was hopeful Thornburg's injury would be a "short-term situation." In that case, he doubted the Red Sox would look to acquire a reliever to help fill the void.
Kelly represents the first in-house choice to pitch the eighth inning. Fellow right-handers Matt Barnes and Heath Hembree also figure to receive late-inning opportunities.
With Thornburg sidelined, Farrell said it's "a strong possibility" that both Fernando Abad and Robby Scott will be on the Opening Day roster. They would join Robbie Ross Jr. to give the Red Sox three left-handed relievers.