Arsenal goalkeeper Petr Cech will be sidelined for three to four weeks in another huge blow to their Barclays Premier League title hopes.
The Czech Republic international suffered a calf injury as he raced back towards his own penalty area after coming up for a corner in the last minute of his side's 2-1 home defeat to Swansea on Wednesday, a result which leaves the Gunners six points behind leaders Leicester.
Arsene Wenger, whose Arsenal side face their second-placed north London rivals Tottenham on Saturday lunchtime, confirmed the prognosis at his press conference on Friday morning.
"(He will be out for) three to four weeks," the Frenchman said.
"It is not more serious. It is a serious calf injury and he had a groin alert on the first goal and he could not kick the ball properly out because of his groin and maybe compensated a little too much and provoked another muscular injury."
Wenger went on to explain that Cech had a groin issue before the game but trusted him to play only to see his first-choice goalkeeper pick up a different injury.
The same happened with Alexis Sanchez earlier in the season when Wenger played him against Norwich despite knowing of a hamstring problem which then flared up in the game and ruled him out for the festive period.
"We had to make the decision before the game because he had a little groin problem but he declared himself 100 per cent fit," he said.
"Then you have to trust the player. He's 33 years old and he knows his body. If he says he's fit then he is available.
"It is like it is. I focus on the future. You want the players to be tough enough to sometimes be able to play through a little pain. You're never completely perfect before a game in March."
David Ospina will deputise for Cech at Spurs and in the coming weeks - with an FA Cup replay at Hull and a Champions League tie in Barcelona to come as well as league games against Everton and Watford.
The Colombia international came in for criticism after a big mistake in the Champions League defeat to Olympiacos earlier this season but Wenger has backed his man to step up now he is needed.
"I have complete confidence in David and I'm not worried at all on that front," he added.
"If you look at the win-rate of Opsina it is very good as well. I'm not worried at all on that front."