Chelsea boss Frank Lampard has confirmed he does not know whether N'Golo Kante will be fit in time to face Manchester United.
The tireless midfielder has been recovering from a knee injury sustained at the end of last season and flew home from the club's pre-season tour of Japan for treatment.
The 28-year-old was included in Blues' squad for their pre-season friendly against Borussia Monchengladbach and came off the bench for the last 20 minutes as Chelsea drew 2-2 in Germany.
Mateo Kovacic started in the holding role alongside Jorginho and Lampard revealed he didn't want to risk Kante by rushing him back to action.
"That was always the plan [to play 20 minutes]," Lampard told reporters.
"He's working a little bit now and it was just to give him the feeling of match time as he hasn't been able to do that yet as it's an awkward injury.
"I just wanted him to feel it and us to see it as you cannot replicate it unless you do it. It was a good opportunity to do that for him and we'll work hard on getting him fit."
The 41-year-old conceded he is unsure over Kante's availability for the clash on August 11 at Old Trafford, but vowed to help the France star recover as quickly as possible.
"Who knows if he'll be ready for next week or not, but we'll work hard for that," he added.
"We also have to be a bit careful as he's played so many games over the past three seasons and we don't want to rush him back if it's going to be a negative. We'll do our best to get him back."
Kante played a key part in helping Chelsea secure a third-place finish in the Premier League last season, making 53 appearances in all competitions and scoring five times.
