The Boston Red Sox are concerned that Koji Uehara won't be ready to pitch on Opening Day.

Uehara is dealing with a hamstring injury.

The Red Sox will open the season on April 6 in Philadelphia.

"With each passing day that he's not in a game, there's growing concern in the sense of, 'Will he be ready for April 6?' We're just working through that," John Farrell said.

"Three games next week would give him six appearances in spring training. Is that enough? We just have to evaluate the stuff once he gets back in games."