Webster is taking Felix Doubront's spot in this turn around the rotation. Doubront, a left-hander, has been inconsistent this season and his velocity has been diminished in recent starts.
Doubront will be available as a reliever for both Tuesday and Wednesday's games against the Twins. Manager John Farrell said that the plan for now is to get him back into the rotation the next time around.
"I think everyone looks forward to seeing that guy on the mound," Farrell said of Webster. "He's got great stuff. He showed he's got very good poise in the first outing that he made for us. We'll see it again tomorrow night."
The Red Sox hope that perhaps some of Doubront's velocity will come back during his short stint in the bullpen. The club is puzzled by his fastball decreasing, given that they can't find any health problems with him.
Webster had a 2.70 ERA with 26 strikeouts in 20 innings with Pawtucket.
In his lone start for the Red Sox, Webster allowed two earned runs over six innings, walking one and striking out five.
Ian Browne is a reporter for MLB.com. Read his blog, Brownie Points, and follow him on Twitter @IanMBrowne. Jason Mastrodonato is a reporter for MLB.com. Follow him on Twitter @jmastrodonato. This story was not subject to the approval of Major League Baseball or its clubs.