The Rays placed McClanahan (back) on the 15-day IL Friday due to a back injury, Marc Topkin of the Tampa Bay Times reports.
After leaving Thursday's start in the fourth inning with mid-back tightness, McClanahan will officially be placed on the injured list. The Rays believe the injury is "pretty minor" and hope the left-hander misses just two starts. On the campaign, the 29-year-old owns a 3.09 ERA, 1.12 WHIP and 91:35 K:BB in 99 innings. Tampa Bay is recalling Alex Cook from Triple-A Durham to take McClanahan's place on the active roster.