BARCELONA, Spain -- Barcelona's Argentina striker Lionel Messi will be out of action for six weeks after tearing a muscle in his left leg during Tuesday night's 1-0 Champions League victory over Celtic.



Messi is helped off the pitch after injuring his left thigh during Tuesday's 1-0 victory over Celtic.



The Catalan club confirmed on Wednesday that Messi will miss both legs of Barcelona's Champions League quarterfinal encounter.



It will also be a race against time for the 2007 World Player of the Year runner-up to be fit for the semifinals if Barcelona get past an opponent who will be named after the draw on March 14.



Messi picked up the injury after 34 minutes during Barcelona's victory over the Scottish side, which booked their spot in the last eight by easing through 4-2 on aggregate.



It is third time in the last three years that Messi has had the same injury, the last occasion being on December 15 against Valencia, which ruled him out of the 'El Clasico' derby the following week against Real Madrid.



In addition to his chronic problems with his left thigh, Messi has had four other significant injuries in the last two years which have caused him to miss a month or more.



Barcelona coach Frank Rijkaard has been forced to defend the club's medical services in the wake of Messi's latest injury.



"To doubt that they are doing their best is an insult. The medical staff and the club in general are working to prevent these sort of problems. They are working hard but there is always a player that can be injured," said Dutchman Rijkaard.



Messi's injury reopens the door for Thierry Henry to claim his place in the starting lineup. The Frenchman has rarely impressed since his big-money move from Arsenal to the Spanish giants last summer.



Rijkaard also has other options to replace Messi on the right flank in the shape of Portuguese international Deco or teenage Mexican winger Giovanni Dos Santos. E-mail to a friend
When did the Argentine sustain the injury? When did he sustain the injury? Who was ruled out for six weeks with a thigh injury? Who was ruled out? Who has suffered this injury three times? What is the number of times that Messi has suffered the same injury? When did the injury occur? Where is Messi from? Who is out with a thigh injury?
Tuesday night's 1-0 Champions League victory over Celtic. Tuesday night's 1-0 Champions League victory Lionel Messi Lionel Messi Lionel Messi third during Tuesday night's 1-0 Champions League victory Argentina Barcelona's Argentina striker Lionel Messi
question: When did the Argentine sustain the injury?, answer: Tuesday night's 1-0 Champions League victory over Celtic. | question: When did he sustain the injury?, answer: Tuesday night's 1-0 Champions League victory | question: Who was ruled out for six weeks with a thigh injury?, answer: Lionel Messi | question: Who was ruled out?, answer: Lionel Messi | question: Who has suffered this injury three times?, answer: Lionel Messi | question: What is the number of times that Messi has suffered the same injury?, answer: third | question: When did the injury occur?, answer: during Tuesday night's 1-0 Champions League victory | question: Where is Messi from?, answer: Argentina | question: Who is out with a thigh injury?, answer: Barcelona's Argentina striker Lionel Messi