Well, Jordi is going to play full out all the time, using his main weapons of speed and agility. This injury I blame on too many minutes this season, caused by Lucho not trusting his alternatives at LB.
But, I think the reliable, trust-worthy backup at LB has been found. I've seen Sergi Roberto play at that position for 21 minutes total now, and I am already completely convinced that he is better as Barca LB backup than anyone else on the squad. Definitely better than Mathieu, I think better than Adriano, and I see no reason to try out Vidal or anyone else. Sergi Roberto must play, and this is another position he definitely helps the team at. I want to see him start the next three games at LB.