Double-A Northwest Arkansas transferred Lamkin from the 7-day injured list to the 60-day IL on June 10 while he recovers from an unspecified injury.
As a result of the transaction, Lamkin will remain out through at least the All-Star break. The 22-year-old lefty had been climbing up prospect lists after a hot start to the season, compiling a 2.04 ERA, 0.93 WHIP and 53:14 K:BB in 39.2 innings over eight starts between Northwest Arkansas and High-A Quad Cities before being deactivated in late May.