It's possible according to Fabiano himself:

“I’ll be back at April 5^th and we’ll see what will happen. I still don’t know who’s gonna be my opponent, but I think It’ll be Faber. And I’ll be ready for him”, said Fabiano, promising his best for the fight.

 

“I have to be well trained, with no injuries at all and I’m already training for this fight. I sincerely think that I’d complicate his life with my game style. He’s good fighting standing, but I don’t fear his striking at all. The deal is be careful with those elbows, but we’ll see. We’ll set a good strategy for him”.

Fabiano is a beast on the ground.  He's very methodical and eventually just wears you down as he did to Akitoshi Tamura at WEC 37.  However, he's severely one dimensional in my opinion.  It would be a quick turnaround for Faber as he just fought at WEC 38, but suffered no damage in defeating Jens Pulver for the second time.  This would also make sense in that this card is taking place in Chicago, the home of Miguel Torres.  Torres is defending his bantamweight belt on this card, so the WEC could be looking to bolster up the star power with Torres and Faber on the same card.  The same way they did at WEC 34 in what still remains the highest rated WEC show on Versus.