With the moves, the Sox have 35 players left in Major League camp, 30 of which are on the 40-man roster.
Though Christian Vazquez and Blake Swihart are the catchers in the farm system generating the most buzz these days, Butler is also well regarded and could be counted on to help at some point this season.
"As we mentioned to him on the way out, if the need were to arise, we've got one of three catchers we feel are a foul tip away to come up and replace someone if that need were to happen, so Daniel is clearly in that mix," manager John Farrell said.
Hill, who pitched for the Red Sox from 2010-12, knew it would be tough for him to win a roster spot, given Boston's depth of lefties. And after dealing with the tragic death of his newborn son, Hill arrived in camp in the first week of March.
"Honestly, I thought he did a great job of somewhat catching up to speed under the difficult circumstances he came into camp under," Farrell said. "And we just, it's going to take a little more time to get back to the arm strength that we typically know him at, to have. Innings are starting to dry up a little more now that the starters are getting deeper. That was the move made."
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.