James Blake says he experienced renewed pain in his knee during a 6-2, 6-4, 6-4 to Robin Haase in the first round of Wimbledon, adding that he may consider retirement if the problem continues.
"If it doesn't get better soon, I'm not sure how much longer I want to play in pain," he said. "It was feeling great in Eastourne, and then had a little setback.
"No excuse for the way I played today. I played with this for quite a while in a bit of pain... it go to a point where I just couldn't take playing at 80 percent."
Blake underwent PRP (platelet-rich plasma) therapy on his knee, a procedure where concentrated blood is reinjected into the injured area, but following his usual practice, did not take an antiinflammatories or painkillers.
The 30-year-old American said he would see how the injury progresses over the summer. "Obviously now I've got two weeks where I'm not playing a match. I'll see how it reacts to new treatments," he said. "If [the option] is continuing to play in pain, I'll reassess after the Open and see if I want to continue that. If I need to, after the Open, take the rest of the year off and then see if I can start fresh in 2011.
"It's a bit of an unknown."
The problem also affects the amount he can practice, Blake added. "Something like this, and overuse injury, it's a tough balance to have to find," he said. "I want to be out there hitting, but I might be doing more harm than good."