Injured five-time major champion Phil Mickelson will tee it up in thePGA Tour Houston Open this week, he said Wednesday, adding that it's his bestchance to keep his Masters bid on track.Mickelson withdrew from the Texas Open last week in the third round with a musclestrain in his back.He flew home to California for treatment, then travelled to Augusta National to getin a couple of days of preparation for the first major championship of the season,which starts next week.The Masters is already without world number one Tiger Woods, who said Tuesday hewould miss the event for the first time in his career after undergoing back surgery. Mickelson, 43, is hoping he'll be fit for a run at a fourth Masters green jacket."I played nine holes today at Augusta and I felt pretty good," Mickelson said onWednesday on his website, philmickelson.com.He added that reports on Tuesday he had withdrawn from Wednesday's pro-ambecause of his injury were "inaccurate".He said Houston Open officials had asked him "months ago" to host a pro-am dinneron Thursday rather than playing in the pro-am and he had agreed."I'm thankful for that, it gives me more time to spend with more of their sponsorsand another day at Augusta," he said."I feel that to give myself the best chance at the Masters I have to play in Houston,"Mickelson said. "If I thought I would injure myself further I would have withdrawnfrom the tournament, but the last few days have been good."Mickelson is due to tee off at 7:50 am (12:50 GMT) in one of the first round'smarquee groups with former US Open champion Webb Simpson and former PGAChampion Keegan Bradley.Other elite names in the field include world number seven Rory McIlroy of NorthernIreland, who will play the first two rounds with England's Luke Donald and AmericanDustin Johnson.Sweden's Henrik Stenson, the reigning US PGA playoff and European Tour Race toDubai champion, will play the first two rounds grouped with Americans Matt Kucharand Jimmy Walker. Mickelson, though, remains in the draw for the first two rounds of the $6.2millionHouston Open which gets underway on Thursday.D.A. Points is the defending champion in the $6.2 million (4.5 million euros)tournament at the re-named Golf Club of Houston.Points held on after a lengthy rain delay last year to fire a six-under 66 in the finalround and edge Stenson by one stroke.Last year Stenson's finish allowed him to play the Masters, this year it will serve ashis final tune-up for the one major championship in which he has yet to post a top-10 finish. Source: AFP