The Red Sox have removed left-hander Justin Thomas from their 40-man roster, Alex Speier of WEEI.com tweets. In corresponding moves, the Red Sox optioned Clayton Mortensen to the minor leagues and selected the contract of Daniel Nava. It's not clear if the Red Sox designated Thomas for assignment or released him.
Thomas, 28, appeared in seven games for the Red Sox this year, allowing ten hits and two walks in 4 2/3 innings while striking out four. He has a 4.14 ERA with 8.1 K/9 and 3.8 BB/9 in eight seasons as a minor leaguer.