Arsene Wenger is optimistic Alex Song will be fit for Arsenal's UEFA Champions League tie in Barcelona to ensure he does not have to gamble on Sol Campbell.
With William Gallas sidelined for Tuesday's game at Camp Nou after aggravating a calf injury in last week's first leg, Song was expected to partner Thomas Vermaelen in the return.
However, Song hurt his groin when playing in midfield against Wolves on Sunday and is a concern for the game in Spain.
Wenger will monitor the Cameroon international's fitness, but is hopeful he will be able to call on Song for the second leg of the quarter-final.
"Song had a groin problem and we will assess him ahead of Tuesday, but he should be OK," said Wenger, whose team came from two goals down to draw 2-2 in the first leg.
"The problem we have at the moment is that we are short. We rested Diaby, Clichy, Nasri, Bendtner against Wolves and we have Fabregas, Gallas, Van Persie, Arshavin out.
"Can you believe that? That's eight players. Any injury now can hit us very hard."
If Song fails to recover in time to face Barcelona, Wenger will have to rely on Campbell to partner Vermaelen again in defence.
Wenger, though, is concerned about asking the 35-year-old to play a full game against the holders after he featured for 90 minutes against Wolves.
He added: "That's a decision I will have to make with him and see how he feels.
"The pitch is massive over there in Barcelona and we will see how he recovers. But it is just two games in four days."