( CNN ) -- Tiger Woods is dealing with a back injury and does n't know if he 'll be able to play at the Masters next month . He may not be the only multiple major winner from the U.S. struggling to be ready for Augusta . Phil Mickelson -- a three-time Masters winner -- pulled out of the Valero Texas Open on Saturday after sustaining a pulled muscle . He got through half of his third round but then stopped . The Golf Channel said he injured his right side . Mickelson earlier this year skipped the Farmers Insurance Open with a back complaint . `` My back 's feeling great , my body 's been feeling great , '' Mickelson said in a statement posted on the PGA 's website . `` I felt as good as I have all year . My speed is back , I was hitting the ball hard , driving it great . `` I pulled a muscle on my downswing trying to hit the ball hard on the ( first hole -- his 10th ) . It just killed and it would n't subside for 10 or 12 seconds . `` I 'm going to go back to San Diego for a couple of days and have a doctor take a look at it but there 's really not much you can do for a pulled muscle . I hope I 'll be OK to play the ( Shell Houston Open ) but I just do n't know . '' Mickelson barely made the cut at the Texas Open . `` As you might imagine , he 's trying to get ready for Augusta , he 's hitting a lot of drivers , hitting them harder , '' his caddie , Jim Mackay , told the Golf Channel . `` He hit one off the first tee , his 10th hole today and just felt a little pain in his side . `` It continued on for a few minutes and he just decided that he did n't want to take anything to chance relative to what 's going on the next couple weeks . ''
Phil Mickelson withdraws from the San Diego Open midway into his 10th round . Phil Mickelson suffers a pulled muscle and hopes he 'll be fine for his next event . The world No . 5 's injury comes weeks before the Masters at Augusta . World No . one Mickelson is dealing with a back injury himself .