The Open 2011: Paul Casey waits on foot injury tests

Casey finished with a two-over-par 72 at Royal St George's

Paul Casey will undergo an MRI scan this week to ascertain the cause of a toe injury that has dogged him over the first half of the summer.

The Surrey-based Gloucestershire-born golfer completed the 140th Open Championship with a two-over-par 72 at Royal St George's.

But he admits to having been troubled in this week's cold conditions in Kent.

"It might be arthritis as the tests are negative and it's been more painful and swollen in the cold," he said.

"But, if that's all it is, I can control it as I know there's some good medication."

Casey still dropped five shots in his closing Sunday round to post a finishing score of 293 - 13 over for the championship.

But he showed his class in a six-hole run around the turn which he negotiated in three under, thanks to birdies at the long seventh, the ninth and the par-three 11th.

"That's the best I've struck the ball all week," he said. "I drove it well, apart from one on the back nine which cost me a bogey. And I feel now that I'm really looking forward to the second half of the season.

"I'm playing in Canada next week, followed by Akron, then the US PGA. That'll be a nice run of tournaments in warm weather, which should be better for my toe."

After finishing third at St Andrews a year ago, it was a disappointment to finish so low down the field this time for Casey.

But he refused to use the excuse of getting on the wrong side of the weather.

"I played on the bad side of the draw at Birkdale in 2008 and finished seventh, so did Ian Poulter and he finished second and so did Padraig Harrington and he won it, so you can't always blame the draw."