GLENDALE, Ariz. -- Erik Bedard's comeback attempt will have to wait.The veteran left-hander, competing as a non-roster invitee to make the Los Angeles Dodgers' roster as a long reliever, will be out four-to-six weeks with a strained muscle in his back, Bedard told reporters. He underwent an MRI exam Monday morning.The injury, a strained Teres major muscle, is the same injury that kept Clayton Kershaw out five weeks last season.Bedard was 4-6 with a 4.