Diego Costa
Costa has been a pivotal figure for Chelsea during his first season at Stamford Bridge.Getty Images

Chelsea manager José Mourinho has confirmed that Diego Costa is back in first-team training, but a decision has not yet been taken as to whether the striker will start against Stoke.

Costa, the Premier League's joint-top scorer with 20 goals so far this term, was replaced by matchwinner Loic Remy with 15 minutes remaining of the nervy 3-2 victory over Hull last month after suffering a recurrence of an old hamstring problem.

A similar injury prevented him from featuring for Spain in matches against Ukraine and the Netherlands during the recent international break. But it appears that rest has allowed the former Atletico Madrid favourite to sufficiently recuperate ahead of Chelsea's final eight games of the season.

"Diego trained (on Thursday and Friday) with the group. He's not injured. I don't know if I start with him or not," said Mourinho. "We did all the tests and the scans to confirm two days ago the situation, and in this moment the muscle is fine. But football is more than that. You need confidence. You don't need to break your intensity. That's our doubt. Let's see next 24 hours."

The Chelsea boss also revealed that Eden Hazard will shake off tiredness following two outings for Belgium to start against Stoke.

Mikel injury concerns

Aside from Costa, Chelsea's only other selection concern of late has surrounded John Obi Mikel.

The long-serving midfielder has been ruled out since February with a knee issue that eventually required minor surgery. Although he is no longer injured, it seems he is not ready to return this weekend.

"We have no injuries, but Mikel is not selected, he is fine and working all week but he very tired so he is not selected but not injured," Mourinho added.

Premier League leaders Chelsea welcome Mark Hughes' Stoke to Stamford Bridge on 4 April knowing that a victory will only increase the pressure on Manchester City ahead of their visit to Crystal Palace.

Mourinho's side, who have led the way at the top of English football since August in their bid to secure a first title since 2010, currently boast a six-point buffer and a game-in-hand over their nearest title rivals, although a slightly lacklustre run of only one win from their last four top-flight home fixtures will need to be swiftly corrected if they are to finish a dominant campaign in relative comfort.