Layne, a 29-year-old veteran of the Minors, has been dominant for Pawtucket, going 5-1 with a 1.50 ERA, while striking out 46 over 41 2/3 innings.
"He's continued what he did in Spring Training, -- and that is that he's very successful against left-handers," said Red Sox manager John Farrell. "He's had decent ability to get good right-handed hitters out, so he's not solely a situational type of lefty reliever. The performance has been very consistent."
Ian Browne is a reporter for MLB.com. Read his blog, Brownie Points, and follow him on Twitter @IanMBrowne. Steven Petrella is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.