Tiger Woods' decision to play in next week's Masters could take some pressure off Rory McIlroy, just as Paul McGinley predicted.

"Look what happened at the US PGA last year," McGinley said last month. "All the talk was 'is Tiger going to play, is he not going to play?' At the time Rory was favourite, but all the expectation, all the talk, all you guys [the media] were focused on was Tiger. Rory didn't sneak in the back door, but he was able to go about his business without the attention on him."

Whatever about the effect Woods' presence has on McIlroy next week, his announcement on TigerWoods.com came shortly before Phil Mickelson charged into the lead in the Shell Houston Open.

The left-hander and three-time Masters champion shot a five under 67 to take the early lead on 11 under par before Andrew Putnam shot 65 later in the day to overtake him at 12 under par.

“I know that for me to have a good chance next week, I’ve got to play well this week. I’ve got to get into contention,” said Mickelson, whose sharp short game has been key. “I’ve done that so far.

"I’ve got to continue to stay focused, hit shots and be sharp throughout the weekend. If I’m able to do that, that will give me momentum heading into next week. You have to be in contention in tournaments and playing well heading into (the Masters). 

"Although it’s happened in the past where guys have out of nowhere played great that week and had a magical week and won, the odds aren’t in your favour. The pressure that you feel trying to win the Masters is greater than just about anything we have.”

Like Mickelson, Pádraig Harrington will also have two more rounds to get his game sharp for Augusta National.

The Honda Classic winner had a great ball-striking day, missing just one green in regulation and making five birdies and just one bogey in a four under 68.

The Dubliner birdied two of his last three holes to move up to 41st on five under but Darren Clarke shot 77, dropping six shots on his back nine to miss the four under par cut by eight stokes.