Arsenal striker Thierry Henry could be out for up to four weeks with a groin injury.
The Frenchman missed Arsenal's shock 2-1 defeat at Middlesbrough, which left the Gunners nine points behind league leaders Chelsea, albeit with a game in hand.
Henry's extended absence will be another blow to Arsene Wenger's men.
He is set to be sidelined as Arsenal face FC Thun and Ajax in the Champions League and Everton, West Ham and Birmingham in the Barclays Premiership.
"I have been suffering with pain on my left groin for some while - right back to March - and I need to rest. It is a disappointment but I have no choice," Henry told The Sun.
"I had some scans on Friday and was told to take at least three weeks' rest, although it could be a month.
"The injury has come and gone since last season. When we were playing one match a week right at the start of the season, it was not so bad.
"But now it is a game at the weekend and a game in the week. I have noticed the difference and the groin has become more painful.
"I knew my body wasn't right and I just have to rest. I don't want to copy what I did last season when I played on with an injury."
That Achilles injury led to Henry missing the end of last season – including the FA Cup final win over Manchester United.
