The Brazilian-born Spanish striker has 13 goals for the high-flying Blues so far this term, including six in his past eight outings.
The scoring run of Costa has helped Chelsea win 11 matches on the trot and Sky Sports pundit Carragher feels his presence could be vital in Antonio Conte’s men clinching the 2016/17 premiership.
“You think of an injury to Costa, he has been the standout player in the Premier League so far, he looks like the Costa we saw when he first came,” he said on Monday Night Football.
“God knows what happened to some of these players in that year with Jose Mourinho, I think you do not just question Mourinho, question this group of players.
“But I always felt Chelsea would have a good season – I tipped them to come second behind Man City at the start of the season – they have title winners in there, people who have been there, done it before.”