Harrington keeps the stress off his right knee during last year’s Irish Open. Credit: golffile.iePadraig Harrington is battling to be fit for next week’s BMW PGA at Wentworth.

The Dubliner, 39, tweaked a hamstring playing with his children before heading to the US for the Wells Fargo Championship two weeks ago. The injury put pressure on Harrington’s right knee, operated on nearly 12 months ago to repair a cartilage tear.

As a result, Harrington immediately sought medical treatment on Monday and will spend the next week in cotton wool as he counts down to Wentworth and next month’s US Open at Congressional.

Down two places to 43rd in the world, it’s an unwelcome problem for the three-time major who has struggled to find any consistency in his game this season and made just two of his last six cuts.

He recorded a top 10 finish at Quail Hollow two weeks ago but his knee gave him serious trouble during the Players Championship at Sawgrass and he missed the cut comfortably after rounds of 73 and 78.

“It was tough going with my knee, which was giving me quite a bit of pain during the week,” Harrington wrote on his website. “I had expected it to be pretty much gone by the time I started on Thursday but unfortunately it was probably worse.

“The pain was quite severe when it came - a sudden stabbing pain when I made certain movements. A lot of the time I was feeling it just before I took the club away, which was a big distraction and it was also very painful when I was walking on a side slope.

“I had to hit a shot from a grass bunker on the 15th on Thursday - I was standing on a steep slope and it must have taken me a minute to get into position as it was very sore.

“I am still very disappointed to have missed the cut, as I was looking forward to the week and feeling good about my game after the weekend of the Wells Fargo Championship.”

Hardly a week goes by without Harrington announcing another tweak to his game or is set up. He changed his putting routine (amongst other things) at the start of the season and then gave up that experiment mid-way through the opening round of the Masters, citing lack of feel.

Now he’s decided to try a new pre-shot routine that he hopes will reduce his tendency to get distracted over the ball. Ironically, the whole process proved to be a distraction at Sawgrass.

He wrote: “I did some work with Bob Rotella and I decided to change my pre-shot routine, as I wanted to stop looking up before I hit. However, when in action on Thursday I found it a major distraction as I wasn’t comfortable with the new routine.

“I probably should have waited to work on it during my week off before changing it but I liked how it felt on the range and wanted to see how it was in a tournament.

“I went back to my old routine after three holes but I then found it quite distracting too. I am still going to change to the new routine but I will work on it this week so as to get comfortable with it.”