It's been a busy week for Fien, who is with his third organization since Monday. The Tigers designated the reliever for assignment last week and the Red Sox claimed him Monday. He posted 10.2 K/9 and 2.3 BB/9 in 58 Triple A innings last year and made his MLB debut. He has only faced 53 major league hitters, so it wouldn't be fair to judge him on the 7.94 ERA he posted for the Tigers.
The Red Sox now have 39 players on their 40-man roster, according to a team press release.