Andy Murray has ruled himself out of returning to singles in time for the US Open next month.
The former world number one had originally targeted the Flushing Meadows tournament and the preceding events in North America for his comeback, but he has now said that will not happen.
The Scot is refusing to put a date on his return, but knows there is not enough time to be ready for the start of the US hard court swing in August.
"I think it's pretty unlikely just in terms of timing," he said. "I spoke to my team a bit about that on Monday.
"There's just a lot of stuff I need to get done physically, get myself stronger.
"The amount of work I need to do on the court to get ready for singles, the amount of work I need to put in off the court to get myself strong enough to play best-of-five sets, it's still quite a way away unfortunately.
"I would love to play. I need to look, like, pretty long-term with this. I don't want to be having to go through another big operation in a few years' time. I want to make sure the operation I've had lasts for as long as possible.
"To give it the best chance, I need to make sure that I'm physically really strong before I get back on the singles court.
"I said this at the beginning of the grass season, I don't want to put a time frame on it. You guys want a time frame.
"I can't give you an exact time frame because I don't know how long it's going to take for me to physically get to that level.
"I know some people might like it to have taken five months or six months, but it's going to take more time than that, unfortunately.
"Whether that's nine months or 12 months or 18 months, I don't know. I'll do my best to make it as soon as I can. I can't give an exact time frame on this. It's tough."
Murray has been restricted to playing doubles during Wimbledon, but he is doing a pretty good job as he looks like a title contender in the mixed with Serena Williams.
The pair thrilled Centre Court with a 7-5 6-3 win over Fabrice Martin and Raquel Atawo to set up a third-round meeting with top seeds Bruno Soares and Nicole Melichar.
However, pursuing doubles at the expense of getting ready for singles is not something he is ready to do.
"I want to try to prepare and get ready for singles," he said. "If I'm able to train the way that I need to off the court and still maintain kind of, I guess, my performance on it in doubles, I would consider that.
"But, I don't know if I want to go over to the States to play doubles for four or five weeks. I'm not sure. I'm not sure yet.
"I'll decide on that probably when the tournament's done and sit down with my team.
"But having felt how I felt these last few weeks, I'm positive about the future, so therefore I'm going to train properly to try and give singles a go. But that will take time."