OPEN Champion Henrik Stenson admitted if it were not for the FedEx Play-Off Series and the Ryder Cup later this month he would be side-lined with fears of another operation on an injured knee.

Stenson two-putted the last for birdie in a three-under-par 68 on the opening day of the Deutsche Bank Championship at TPC Boston.

It put the Swede, who is set to contest a fourth Ryder Cup starting on September 30, just two strokes behind the leading duo of Surrey’s Paul Casey and Argentinean Fabian Gomez.

But despite Stenson’s solid start in the $8.5m second event of the PGA Tour’s FedEx Cup Play-Off Series concern for his knee must place doubt on his fitness heading to Hazeltine.

And this is after the current World No. 4 withdrew from last week’s Barclays Championship with the same concern.

“I have a slight tear in my meniscus but in a different place compared to where I had my operation in December,” he said.

“So I just have to try and manage it and see how it plays out. I know what I am dealing with at the moment and I just have to see over time how the knee is going to perform and also consider if I will have to have another operation.

“I would prefer not to have the operation and it’s as such I just can’t make a decision but I can say if this wasn’t the FedEx Cup and the Ryder Cup was not at the end of the month then I possibly would not be playing.

“The thing is with the schedule this year there has been a lot of golf and not much time in between to recover.”

And Stenson is not the only one suffering with Scotland’s Russell Knox heading to see the Tour’s doctor after his round of a two over par 73.

Knox had been suffering a mystery virus last week on Long Island, and something he said he picked-up from his wife’s niece but was clearly no better a week on.

“I’m really struggling with my health and it’s a legacy from last week and I just can’t seem to shake it so that’s why I’m heading off to see one of the Tour’s doctors,” he said.

“I thought I was getting better but I am actually feeling worse and just struggling with my energy and feeling very tired”.

Knox had begun his round in brilliant manner holing an 18-foot birdie putt but also included three bogeys in four holes from his 11th.

And Marin Laird is projected to drop out of this FedEx Cup after posting a four-over par 75.

Included in Laird’s round was four birdies but included in his round was back-to-back double bogeys at eight and nine and a bogey at 10.

Laird is currently ranked 63rd in the Play-Off standings but with the Tour indicating he would drop to 80th and with the top-70 at the close of the event on Monday only progressing to the Tour Championship in Atlanta.