By Chelsea correspondent Tony Hughes

Chelsea want Diego Costa to have three months off to cure his persistent hamstring injuries, Football Insider sources understand.

The Premier League leaders have designed a personal rehabilitation programme for Costa aimed at getting him fully fit for the start of next season.

The Chelsea striker will be given an extended period of rest from football as well as a daily regime of strengthening exercises on his troublesome left leg.

Football Insider understands the Spain international will withdraw from international duty next month to go on an early summer break and will gradually start building up his strength when Chelsea return to pre-season training in the first week of July.

Jose Mourinho and his staff do not want Costa to play competitively until August, when preparations for the new season are in full swing.

They believe the striker, who has scored 19 Premier League goals in 24 matches, needs three months to fully recover from the injuries that have blighted an otherwise excellent debut campaign.

Speaking on Friday, Mourinho confirmed he would recall Costa to the team only if the league leaders are struggling to claim the title.

The Brazilian-born forward had been in the mix to face Arsenal last Sunday but, as revealed by Football Insider, Mourinho decided not to risk his leading scorer for that fixture.

Costa has been troubled by hamstring problems since his final few months at Atlético Madrid last year and, having suffered strains before Christmas, suffered a relapse in the victory at Hull in March.

Costa missed Spain’s subsequent international fixtures and, having been thrown on from the bench at half-time against Stoke on 4 April, tore the muscle again in his left leg and was replaced after only 12 minutes. Asked if the striker, who has been taking some part in training over the past 10 days, would feature against Palace, Mourinho said he was “out”.

“It’s not been a setback but it just isn’t worth the risk,” the manager explained. “In this process, in the last month, if we lose a game and we don’t want to lose a second match, he will be back immediately. But, because the results in the last month were always victories and a draw against the team in second [Arsenal], we don’t need to rush him. We are trying to give him maximum stability for him to be stronger and stronger. No need for any risk.”

Mourinho, who will have Loic Remy fit to return on Sunday after calf trouble, was asked if it was likely Costa would feature again this season. “There is a chance he might not,” he said of the 25-year-old. “If we win Sunday, I would say he doesn’t play next week against Liverpool. If we don’t win on Sunday and we need points against Liverpool, I’d say he would play against them. It’s about judging it result after result. If we don’t need him, probably he doesn’t play.”

Costa has begun a personal rehabilitation programme aimed at strengthening the hamstring in the hope he does not suffer similar problems. Mourinho said: “We are preparing a good working situation for him during the holiday period where he can obviously mix the holiday with work without fear.”