From Brian Keogh at Royal Birkdale

Padraig Harrington's hopes of defending his Open title were hanging by a thread last night.

Nursing a painful wrist injury that forced him to abandon two attempts to play a practice round, he will be doubtful right up to his 7.58 am tee time.

Harrington reckons he only has a "75 percent" chance of teeing it up at all and calculated that he is no more than 50-50 to complete all 72 holes.

But he is praying that a change of anti-inflammatories, intensive treatment from chiropractor Dale Richardson and some powerful pain-killers will work a miracle.

Harrington said: "Yesterday I was fully sure that I would play, just worried that I would inflame it when hitting a shot out of the rough or a bunker or something. Today I am not so fully sure I’ll play.

"It's 75 per cent that I will tee it up and 50-50 that I can keep going for four days on top of that. I’m going to give it every chance to play and if there is pain I am still going to play anyway.

"The plan is to get to the range, warm up and see what it is like. I will probably take some painkillers but I don’t believe in cortisone injections. I’m disappointed because there seemed to so much improvement in the injury yesterday."

Harrington's big worry is not the pain he feels in his right wrist and upper forearm but his ability to commit fully to his shots, especially in the rough.

He explained: "It is just the doubt of going through impact. It is the flinching and the intimidation of hitting the ball when there is pain, not the actually amount of pain.

"I am not too concerned about how much pain there is, it’s just whether the pain is affecting my ability to commit to hitting the golf ball.”

Harrington hit two long-iron tee shots off the 10th tee and after ignoring one in the rough, he felt a shooting pain as he hit a six-iron from the fairway and left the course for treatment.

Returning 20 minutes later with strapping on his wrist, he hit just one tee shot but felt more pain and limited his practice to a walk around the course. chipping and putting occasionally.

Smiling he said: "It's been a relaxing couple of days. I tried to to watch other people hitting the shots so I could judge what way the ball was flying like.

"I haven’t played the back nine at all. But the preparation I’ve had is as good as I could do. I won’t have any hang ups over it. I hope to go and play and when I do, I hope to see all the shots."

American Heath Slocum will replace Harrington in the ninth threeball of the day alongside Retief Goosen and Justin Leonard, if he fails to make it to the first tee.