Scotland: Argentina`s Juan Martin del Potro could sit out a potentially make-or-break Davis Cup semi-final decider against Great Britain on Sunday after playing for an exhausting eight hours over two days.
The South Americans lead the defending champions 2-1 going into Sunday`s reverse singles where three-time Grand Slam winner Andy Murray is expected to see off Guido Pella.
That would set the scene for the decisive clash which is expected to feature 2009 US Open champion del Potro against Kyle Edmund.
But del Potro, still feeling his way back after a series of wrist injuries pushed him to the brink of retirement, says he is concerned for his long-term health after a tiring summer which saw him make the Olympics final and the quarter-finals of the US Open.
"I`m not thinking about tomorrow. First Guido Pella has to play against Great Britain`s number one and he could win and close the tie," said the 27-year-old del Potro who beat Andy Murray in five sets on Friday in a rubber lasting over five hours.
It was del Potro`s longest ever match and he was back in action on Saturday partnering Leonardo Mayer in a 6-1, 3-6, 6-4, 6-4 loss to Andy and Jamie Murray in the doubles.
"Of course I feel something bothering me with my body but that is normal," added del Potro.
"I didn`t expect to play eight hours in two days. That is enough for me at this moment in my comeback."
"I`m doing great and I didn`t expect to play at this level. I have already beaten the top four guys in the world in the past two months but my biggest aim for this year is to finish it healthy.
"If something were to happen to me in these situations I would be very sad and I want to take care of my health. I fought a lot and spent a lot of time to come back to this situation.
"This is just the beginning of my new career. I want to play for many more years not just a few more matches."
In the absence of Del Potro Argentina could call on either Federico Delbonis or Mayer.
Andy Murray says he still believes Great Britain can book a place in the final.
The holders found themselves trailing 2-0 after the opening day`s singles rubbers with Murray`s loss to del Potro followed by Edmund being beaten by Pella.
"I`ll give it my best effort tomorrow. Whether I win or not, I don`t know. But I can definitely guarantee I`ll give it my best effort to win," added Murray.
"Hopefully I can and it makes it interesting if it goes to a fifth rubber. But I`m not going to be the fresher of the players going in to the match. I`ll be tired and I have to except that and deal with it and try and play the match on my terms if possible."
Great Britain beat Belgium in last year`s final while Argentina are trying to reach a fourth final in 10 years.