Messi was in tears as he went off

The 20-year-old went off in tears after suffering a tear in his left leg.

He will now miss the quarter-finals of the Champions League and will struggle to be fit for the semi-finals if Barcelona reach that stage.

"He is an important player for us and this is a sad moment for the players," said Barca coach Frank Rijkaard.

Messi spent a lengthy spell on the sidelines with a similar injury during December and January.

It is the fourth time the Argentine has suffered this type of injury in the last three seasons.

606: DEBATE How big a blow is Messi's injury?

The Argentine was rested for Barcelona's game against Atletico Madrid in the build up to the second leg of the last 16 against Celtic.

Barcelona lost 4-2 and the decision courted criticism from the media, who clamoured for him to play against the Scottish side at the Nou Camp.

"The doctors spoke and said there was a risk of injury and you (the media) put pressure on him to play, saying that he always has to play," said Barcelona defender Carles Puyol.

"Now we're all left to regret the decision.

"On Saturday (against Atletico) there was more risk than on Tuesday, but if he hadn't played and we had got a bad result I'm sure you would have said it was because he wasn't on the pitch.

"Leo's injury is bad news, so now let's see what you have to say about that.

"You've got to leave the doctors and physios to do their job because they know more about these things than you do."