Per rotoworld (and other sources)

Grady Sizemore is unlikely to be ready for Opening Day after straining his back while fielding grounders in the outfield two weeks ago.

Here we go again. Sizemore was cleared last month to resume baseball activities following offseason knee surgery, and he evidently hurt his back while rehabbing his knee. It's a big blow to the Indians and yet another physical malady to add to Sizemore's laundry list of ailments. While Sizemore is out, the Tribe will likely shift Michael Brantley over to center field while giving Fred Lewis, Felix Pie, Aaron Cunningham, Ryan Spilborghs and others a shot in left field.

Blech. At least it gives us a slightly extended look at Cunningham/Spils.