As Thomas notes, the acquisition of Ryan Hanigan as a backup to Christian Vazquez and the presence of Blake Swihart on the 40-man roster made Butler an expendable asset for Boston. The 30-year-old Butler made his Major League debut in 2014 after signing with the Sox as an undrafted free agent in 2009. He posted a .618 OPS in a small sample of 20 plate appearances but has a nice track record at the Triple-A level. In 192 games (739 PA) with Pawtucket, Butler slashed .248/.329/.416 with 22 home runs while throwing out 31 percent of those who attempted to steal bases against the PawSox.
The D-Backs strike me as a possible fit for Butler, given their lack of depth behind the plate. The Orioles are another team that has been linked to backup catching options (despite already having five backstops on their 40-man roster). Of course, as Thomas notes, Butler could end up back with Boston on a new minor league deal if he isn’t traded and passes through waivers unclaimed.