Costa has been prolific this season for a Chelsea side five points clear at the top entering this weekend’s fixtures.
The Blues declined to comment on reports the 28-year-old had had a disagreement with head coach Antonio Conte and his coaching staff.
Conte yesterday said he had some undisclosed doubts for the game, but mentioned no names or reasons for potential absences. Eden Hazard could play in a central striker role in Costa’s absence, just as he did against Bournemouth, when the former Atletico Madrid striker was suspended.
Costa helped Chelsea to the Premier League title in his first season in England in 2014-15, but was poor as the Blues’ title defence ended in a 10th-placed finish last term.
He was also among the players blamed by a section of Chelsea fans when Jose Mourinho was sacked by the Blues for a second time in December 2015. Costa was repeatedly troubled by hamstring problems and disciplinary issues in his first two seasons at Stamford Bridge and was repeatedly linked with a return to Atletico. Costa was earlier this month subject of speculation over a mega money move to the Chinese Super League.
It was rumoured Tianjin Quanjian were prepared to bid £80 million and Costa’s future could be the main talking point of the winter transfer window, which closes on January 31.
Costa signed a five-year deal on his arrival in July 2014 for £32m, so has two-and-a-half years to run.
He appeared to have overcome his fitness and disciplinary issues under Conte, with whom his relationship appeared strong.
The 28-year-old has scored 14 goals in 19 Premier League appearances this term and was many pundits’ player of the season at the halfway mark. His understanding with Hazard and Cesc Fabregas, in particular, had troubled opponents to the extent Chelsea won 13 straight games until the loss at Tottenham on January 4.
The trip to Leicester is Chelsea’s first Premier League game since the defeat, coming after a FA Cup third-round win over Peterborough, when Costa was among the substitutes.
Now his future at Stamford Bridge is in serious doubt.
Meanwhile Leicester boss Ranieri believes Premier League leaders Chelsea are far from guaranteed the title “They can be caught,” said the 65-year-old, who managed Chelsea between 2000 and 2004. “They started not so well but after a few matches Conte understood the team and the players.
“They made a good start and lost to Tottenham after 13 (straight wins) which is an amazing achievement.
“We expect a lot from them but we are ready to fight and win. Yes it’s harder (to win from the front).
“But I think everyone wants to be up there and not behind, that is much better. But the league is very long and they must be careful.”