I don't know if Rafa will play Lucas in such a critical game, but I do know that he was thrown into the derby, with no prior EPL experience, replacing Steven Gerrard. That shows some confidence from his manager. He also put a shot on target that would have been the winning goal. He's a very calm, collected player at the center of the park, and while it's a very critical game, I don't necessarily think it's all that difficult of a game. Difficult environment? Yes. But Lucas is a classy player and probably better than anyone Besiktas will put on the pitch.
I agree about Gerrard on the right. I'm definitely not against him playing out there, though he does pinch inward, allowing the opposing left middie and/or fullback to make runs up the left-hand flank. That's really the only problem, though if Masch/Momo/Lucas is there to support him, it makes it less of a burden.
From what I've read Swagger will not be fit for tomorrow's match. I'm hoping he's ready to go on Sunday. Arsenal's forwards (particularly the suddenly in-form Walcott) will give Sami fits.
I'm hoping for a draw in the Porto-Marseille game.