Eickhoff suffered a mild lat strain and is out six to eight weeks, Meghan Montemurro of The Athletic Philadelphia reports.
Eickhoff was limited to just 24 starts last year with back and hand injuries and now will have to start this season on the disabled list. If the original timeline holds, he'll be back in late April at the earliest. The injury re-opens the competition for the Phillies' fifth starter spot, which had been previously made unnecessary by the signing of Jake Arrieta. Mark Leiter, Ben Lively and Zach Eflin now have a chance to open the season in the rotation, though with extra off days in early April, the team could elect to begin the year with just four starters.