Tiger Woods will have until 10 minutes before his tee time of 8:35am on Thursday to decide whether to play in or miss the US PGA Championship at Valhalla.
Woods is a major doubt for the final major of the year after withdrawing from the WGC-Bridgestone Invitational during Sunday's final round at Firestone Country Club.
The former world number one looked in severe pain from his back after hitting his tee shot on the ninth hole in just his third tournament since undergoing back surgery on 31 March.
Woods has yet to announce if he will able to play at Valhalla, the venue where he won the US PGA in 2000 in a play-off with Bob May, and his scheduled press conference on Tuesday was postponed.
The 38-year-old has previously missed two majors in a season, but never three. That now looks a distinct possibility.
Knee surgery in 2008 to replace his anterior cruciate ligament - just after his last major victory in the US Open at Torrey Pines - forced him to miss the Open and US PGA Championship.
In 2011 he failed to tee it up at the US Open and the Open because of an Achilles complaint.
Colin Montgomerie believes Woods "will suffer" if he does decide to play in the event.
Montgomerie told BBC Radio Five Live: "I saw the TV pictures on Sunday evening and really, how can he can play again this year, never mind within three days?
"Whether he can handle this I'm not sure. This is a big golf course, the rough is heavy again. He's hitting the ball I hate to say, not straight, he will be in the rough and he will suffer.
"Whether it's good for his long term future in the game to play here or not I am not sure. Obviously we would love him to play, it's a bigger and better event when he does."
Montgomerie has not played in the US PGA since 2010 and made the cut just twice in his last nine appearances, but qualified courtesy of winning his first of two senior major titles this season, the Senior PGA Championship in May.
And the former Ryder Cup captain believes Woods will have to be honest with himself and US captain Tom Watson if Watson considers him for one of his three wild cards for Gleneagles.
"It would be very difficult to say if Tiger was fit, not to pick him," Montgomerie added. "Can Tom go to Gleneagles and, the horrible thing is, lose having left Tiger Woods here?
"He has more of an excuse now because Tiger might not be fit for five rounds in three days. He has to take players who can play five rounds in three days. Can he play that? Right now the answer is no.
"Tiger has to sit down and be very, very honest with Tom Watson and say 'Am I going to help you? Can I win three and a half out of five points?'.If he can say that obviously you take him. If he's honest, right now, it's no, but he's got this week to prove himself."