"I gave up a couple of hits, but we had some superb plays out there. I'm happy I was able to put up a zero," Tazawa said. "The velocity was there, but I think I should have kept my emotions a little more in check."
Tazawa's previous relief appearance was against the Angels on July 3 before he was placed on the DL with a right shoulder impingement. Unlike reliever Koji Uehara, who is on the DL with a right pectoral strain, Tazawa's injury was building over time.
"[The injury] was probably more accumulative," Red Sox manager John Farrell said. "It wasn't one event that caused any kind of soreness or caused us to back him out of the way."
Tazawa has had an important role in the bullpen this season, posting a 3.62 ERA in 35 relief appearances before the injury. The righty struck out 37 batters while walking eight over 32 1/3 innings, holding opposing hitters to a .215 average.
The skipper said the time off was beneficial for Tazawa's shoulder recovery, but he will keep an eye on the frequency of his outings.
"Yeah, I think that's gonna be dependent upon the number of pitches, the stress to them all," Farrell said. "That'll be something we continue to monitor going forward."
• Uehara received a platelet rich plasma injection on Friday. The Red Sox are still unclear on the severity of his pectoral strain.
"He went through a PRP injection today. So that's going to require a little downtime, to recover from that," Farrell said. "Still doesn't lend to a return date, or really, to put a ball back in his hand as of yet. So that's really the most update that I can give you."
Deesha Thosar is a reporter for MLB.com based in Boston. This story was not subject to the approval of Major League Baseball or its clubs.