Alex Wilson was sent back down to the Minors after working 2 1/3 innings in Saturday's loss.
"We needed it," Farrell said of Wright's promotion. "Needed length, we needed another fresh arm. He's been throwing a lot of strikes. He's pitched out of the bullpen for us here in the past. In the event that something we're to happen unforeseen to Clay [Buchholz] early on [in Sunday's game], we needed to protect ourselves with length."
At Pawtucket, Wright is 5-2 with a 2.80 ERA in 11 starts.
"I think the biggest thing is his strike throwing ability has been consistent and the action to the pitch has also been as consistent as the strike throwing," Farrell said. "There's a uniqueness to his style, we know. A contrast. And this isn't the first time he's been here."
Ian Browne is a reporter for MLB.com. Read his blog, Brownie Points, and follow him on Twitter @IanMBrowne. This story was not subject to the approval of Major League Baseball or its clubs.