Gary Cahill of Chelsea
Chelsea defender Gary Cahill praises striker Didier Drogba (Clive Brunskill/Getty Images)

Chelsea centre-back Gary Cahill has claimed Didier Drogba is back to his best and is ready to compete with Diego Costa for the number nine role.

After spending eight seasons at the west London club and being a crucial figure in clinching the Champions League crown in 2012, with the striker scoring the final penalty in the shootout that handed Chelsea victory, Drogba returned to Stamford Bridge in the summer after ending his contract at Galatasaray.

With manager also Jose Mourinho bolstering the attack with Costa and Loic Remy, the veteran legend was expected to have a peripheral role this season, but with both strikers struggling with injuries, Drogba has seized the opportunity to prove he still can compete in the top flight.

Costa has returned to training and is expected to regain his place in the line-up for the Premier League game against Queens Park Rangers on Saturday 1 November.

However, Cahill believes Drogba, 36, is an option worth considering. He said: "Does Diego have a battle to get in the team? We have options, not just up front but all over the pitch. It's great."

"To have the three strikers in form, Loic scored before he was injured, to have them all back fit and scoring is vital," Cahill said, according to Standard Sport.

The Ivory Coast striker scored his first goal for the club since his summer return to Stamford Bridge in the Champions League game against Maribor last week and has since netted two more in the successive games against Manchester United and League Two side Shrewsbury in the Capital One Cup on Tuesday 28 October.

"Didier has made a statement over the last week with playing games. We've seen in the last two matches that he's fully fit now," Cahill said.

"He is looking dangerous, like he was before he went [in 2012]. He has been massive for us, led by example at Shrewsbury and got a vital goal for us. Who knows how long he can play on for? That's for the club and Didier to decide. Diego has been playing the majority of the games up till now but Didier is fit and sharp."

Meanwhile, the centre-back hopes to take revenge out on QPR after the club's London rivals beat them 1-0 in January last year.

Cahill said: "We can't take a win for granted. They're in good form. The onus is on us to be on the front foot. Last season we struggled against teams that people thought we would beat.

"Manchester City have a very tough game at the weekend but QPR are coming in off the back of a good result [a 2-0 win against Aston Villa]. I watched them on Monday night and they were great, so this is yet another tough one in the Premier League."