The Los Angeles Galaxy have warned something will have to give as David Beckham embarks on a gruelling schedule for club and country.
Beckham is facing a gruelling three months for club and country
The Galaxy also suggested he could miss some England friendlies.
Beckham, 32, faces at least 22 games, almost 80,000 air miles - across 128 time zones - and nearly a week in the air over the next three months.
"I'm not going to deny there comes a point when your body can't do it anymore," said Galaxy boss Alexi Lalas.
"If at any point we felt it was detrimental to his health or ability to help our team we would take action."
At the end of our match, he looked a bit hobbled and he should have been rested
LA Galaxy coach Frank Yallop after Thursday's 3-0 defeat
Beckham, who has been struggling with an ankle injury, flew back to LA and played all 90 minutes in the Galaxy's 3-0 defeat against local rivals Chivas on Thursday - just 30 hours after appearing for England.
"I wasn't going to play him at all," Galaxy coach Frank Yallop said. "But he wanted to play and realises the situation that the team is in.
"We need points and he's that kind of a guy - at 2-0 down he could have a bit of magic and make a difference.
"At the end, he looked a bit hobbled and he should have been rested."
It capped a busy few days for the midfielder, who made his long-awaited first start for his new team in New York on Saturday before flying to London for England's friendly against Germany on Wednesday.
This week has just been a taste of what is to come as Beckham throws himself into his American adventure whilst trying to help England qualify for next year's European Championships.
Of particular concern are two blocks of four games in nine days and a run of seven games away from his new home in LA in 21 days. His diary is especially crowded around what promises to be a crunch game for England in Moscow on 17 October.
And Beckham will face more games - and travel - if the Galaxy reach the MLS play-offs, which are scheduled for the weeks before England's final qualifier against Croatia.
Sports doctors consulted by BBC Sport have said the former Manchester United and Real Madrid maestro will find it increasingly difficult to perform at his peak as the short-term and long-term effects of air travel mount up.
They have also warned he will become more susceptible to injury - and his body will be less able to recover from injury - as he criss-crosses the globe.
But Beckham's spokesman, Simon Oliveira, told BBC Sport: "We are not worried. David is very confident he will be in peak condition - both for England and his club."
And Lalas said he thought the player would relish the challenge of combining international duty with his Galaxy exploits.
He did, however, warn there could come a time when the club would have to say no to their star's trips back to England for friendly matches.
We want to make sure we get our money's worth and that he is ready to go when he plays for the Galaxy
"We would never stand in the way of a player representing their country," Galaxy boss Lalas told BBC Sport.
"And David's love of England and the honour that it is for him to represent his country is evident from the first time you talk to him.
"But there will certainly be moments when we need to sit down with him and do what's best for our organisation and him.
"There are Fifa dates that we have to abide by and will continue to do so. But if it is a friendly game that doesn't fall on a Fifa date that is obviously something we will have to discuss with the player.
"We have a vested interest in this player and we have spent a tremendous amount of money to retain his services. We want to make sure we get our money's worth and that he is healthy and both physically and mentally ready to go when he plays for the Galaxy."
Wednesday's game against Germany was on a Fifa-sanctioned date and 6 February and 26 March are the two dates set aside for next year's build-up to the European Championships. If England qualify for the tournament they would normally play at least five warm-up games in the preceding months.
Lalas added that no special provisions have been made by the club for Beckham's travel commitments and that he would be expected to fly to games in the US with the rest of the squad.
Major League Soccer rules stipulate that all teams must fly "commercial" flights to prevent the richer clubs from gaining any unfair advantage - the Galaxy do occasionally charter flights but only under exceptional circumstances.
"David Beckham is a part of the Galaxy so he will be expected to be a part of that team and how we travel," said Lalas.
He also confirmed Beckham, who signed a five-year contract with the Galaxy worth a reported £128m in January, would be expected to join the team on their trip to Australia at the end of November for an exhibition match against Sydney FC.