Fister, 33, was claimed off release waivers Friday. He will join the Red Sox on Saturday and start Sunday's series finale against the Los Angeles Angels. Fister opted out of a minor league contract with the Angels earlier this week after making three Triple-A starts.
"Doug has been an established major league pitcher," said Dombrowski, the Red Sox's president of baseball operations. "We've been looking for starting pitching depth. He's a quality individual, hard worker. [He's in] great shape, and we think he can help us."
Fister is 77-76 with a 3.60 ERA in 212 appearances (199 starts) over his eight-year major league career. He went 8-1 with a 1.79 ERA in 10 starts after being acquired by the Tigers in 2011. His best season came in 2014 when he went 16-6 with a 2.41 ERA in 25 starts for the Washington Nationals.
Dombrowski said the Red Sox attempted to sign Fister earlier this season shortly before he agreed to join the Angels. They dispatched trusted special assignment scout Eddie Bane to watch Fister in Triple-A. Fister allowed seven runs on 16 hits and five walks in 15⅔ innings for Salt Lake City.
"For us, this guy's a good pitcher," Dombrowski said. "I know his stuff wasn't quite the same as it was in the past, but Eddie scouted him. I have a lot of faith in Eddie's judgement. He said, 'Dave, he's maybe not quite the same, but he can be an effective big league starter for us.'"
Fister will slide into the rotation spot vacated when lefty Eduardo Rodriguez went on the disabled list with a right knee subluxation and presently occupied by Triple-A call-up Hector Velazquez. The Red Sox are hopeful of Rodriguez returning next month, at which point Fister would move to the bullpen, according to Dombrowski.
But Fister also provides insurance against further injuries in the rotation. Rodriguez has had repeated problems with his knee, while lefties David Price (elbow strain) and Drew Pomeranz (flexor strain) dealt with issues in spring training.
The Red Sox also agreed with veteran infielder Jhonny Peralta on a minor league contract. He will report Monday to Triple-A Pawtucket in an attempt to prove he can be a viable option for the Red Sox at third base.
Peralta, 35, was recently released by the St. Louis Cardinals after failing to record an extra-base hit in 58 plate appearances. The Red Sox have the worst OPS in the majors among their third basemen.
"We had some mixed reports on him during the season," Dombrowski said. "We felt it was an opportunity to go to Triple-A, take a look at him."