Crabtree will not play in Thursday's preseason opener and is expected to miss a week or two of training camp due to an undisclosed injury, CSN Bay Area reports. Crabtree left Wednesday's practice early with what is believed to be a mild hamstring strain. While 49ers coach Jim Harbaugh didn't reveal what Crabtree's injury was, Harbaugh did state it was unrelated to the wideout's foot or Achilles. To err on the side of caution, Crabtree could sit out the next couple weeks to ensure he's healthy as the regular season draws closer. While he's sidelined, Steve Johnson should see more work with San Francisco's first-team offense.