Woods playing fourth tourney of '10

DUBLIN, Ohio -- There were no signs of the injury that knocked him off the golf course three weeks ago but plenty of evidence that the inactivity is affecting his game.

Tiger Woods shot even-par 72 on Thursday during the opening round of the Memorial Tournament at Muirfield Village Golf Club, where he was unable to birdie any of the par 5s and made just two all day.

The effort, in his first round since withdrawing from The Players Championship with a neck injury, left him seven strokes back of first-round co-leaders Geoff Ogilvy, Justin Rose and Rickie Fowler.

"I haven't played," Woods admitted. "This is my 10th round of the year. Usually you're like that in January. Here we are in June. I need competitive rounds. Hopefully I can make some birdies and get up there."

Woods is playing his fourth tournament of the year after his well-documented leave from the game.

After returning to competition at the Masters, where he tied for fourth, Woods missed the cut at the Quail Hollow Championship and then withdrew from the final round at The Players with what turned out to inflammation of a joint.

Following rest and rehab, Woods returned to the Memorial, tournament he has won four times, including last year. But he struggled with various parts of his game, especially short-iron shots. Five times he stood 100 to 121 yards from the green and never managed to hit it closer than 13 feet.

Woods admitted that his wedge game was poor due to lack of play but found some positives in other aspects of his game.

"I was encouraged I was able to hit a few other shots today that I haven't hit all year," Woods said. "I hit some shots ... the shape, the feel ... it felt like it did last year. I just need to get back to them."

Woods hit seven of 14 fairways and 10 of 18 greens in regulation and needed 27 putts. He ended up tied for 50th.

Woods is again in danger of losing his No. 1 ranking this week. Phil Mickelson -- who shot 67 and is in a five-way tie for fourth, two shots out of the lead -- can overtake Woods with a victory as long as Woods finishes no better than a tie for fourth.

But after missing the cut last week at Colonial, Mickelson was not concerned about getting to No. 1.

"I wanted to play well at Colonial, but [the missed cut] gave me a chance ... you've got to take what you have and get a positive out of that," he said. "It gave me a chance to work with Butch [Harmon]. Gave me a chance to work with [Dave] Stockton. Hopefully this tournament will give me a little momentum heading into the U.S. Open."

Woods would like that as well. The year's second major, the U.S. Open at Pebble Beach, begins June 17.

Bob Harig covers golf for ESPN.com. He can be reached at BobHarig@gmail.com.