The injury first came to light in late June, leading to Masterson having his next start pushed back to July 1. In that outing, and in his most recent start Monday, Masterson combined to allow eight earned runs in just five innings. According to cleveland.com, Masterson hinted after his start Monday that his knee was bothering him, seemingly leading to the Indians' move.
Overall, Masterson has gone 4-6 with a career-worst 5.51 ERA this season, just one year after an All-Star appearance in 2013. Since his ERA reached a season-best 3.86 on May 8, Masterson has gone 2-5 with a 7.16 ERA.
He's currently in his last arbitration-eligible season and is set to become a free agent at year's end.
To take Masterson's place on the roster, the Indians called up Nick Hagadone from Triple-A Columbus, where he's recorded a 3.77 ERA in 23 games. Hagadone has pitched in six games for Cleveland this season, allowing two earned runs in three innings.
The Indians also option outfielder Tyler Holt to Columbus, designated pitcher Mark Lowe for assignment, and called up catcher Roberto Perez from Columbus.