Chelsea have been rocked by the loss of goalkeeper Petr Cech for a month.
Cech injured his calf in training yesterday and scans revealed a small tear.
Cech will miss the rest of the club's pre-season programme and is unlikely to feature in the Community Shield against Manchester United at Wembley on August 8.
A spokesman for Chelsea confirmed: "Petr will be out for around a month after scans showed a tear in his right calf.
"He is expected to miss the rest of the pre-season campaign."
Chelsea are covered in Cech's absence by Ross Turnbull and Hilario. Both goalkeepers played a part in Chelsea's double-winning season last term.
Cech missed a month of last season after sustaining a similar injury against Inter Milan in the Champions League.
Turnbull, signed on a free transfer from Middlesbrough last summer, made his debut for the club in the Champions League against APOEL last season.
His Premier League debut came against West Ham and although he conceded the goal which enabled Inter to put Chelsea out of the Champions League at Stamford Bridge, Turnbull had a competent game.
Hilario is the more experienced of the two reserve goalkeepers and is likely to get the nod at the start of the season.
The Portugal goalkeeper, 34, was between the posts when Manchester City defeated Chelsea 4-2 at Stamford Bridge last season but he is almost certain to play against Manchester United in the Community Shield on August 8 and in Chelsea's opening game of the season at home to West Brom the following weekend.Reuse content