Neither set-up man the Red Sox traded for under president of baseball operations Dave Dombrowski, Tyler Thornburg and Carson Smith, is throwing off a mound presently.
Smith, on his way back from Tommy John surgery, felt soreness after throwing a bullpen session and is back to doing long toss.
"He’s had to slow down," Sox manager John Farrell said Thursday. "Once he got on the mound with some aggression and good intensity, was throwing the ball well. And as a result there’s been some soreness that has kind of reared its head. So have had to back him off, back into long toss, he’s thrown out to about 110 feet here today. We’re hopeful that in the very near future that mound progression resumes.
"The unique thing about Tommy John recovery is that every situation is going to be different. In this case, we’ve had to take a step back a little bit and get back to flat ground."
Smith is in Boston as part of a previously scheduled meet-up with the team, Farrell said. When the season began, Smith was rehabbing in Florida. He was put on the 60-day disabled list on Thursday, a formality that opened up a 40-man roster spot for new acquisition Chase d'Arnaud.
Smith was put on the disabled list on April 3, so he can return June 2 at the earliest, but may now need more time.
Thornburg (right shoulder impingement) is building up his long-toss distance.
In other injury news, Brock Holt (vertigo) may begin a rehab assignment with Triple-A Pawtucket on Friday or Saturday, Farrell said.