Stout (13-3-1 MMA, 2-2 UFC) fought just hours ago at UFC 80 in Newcastle, England dispatching Per Eklund via unanimous decision. Stout is a long-time veteran of Canadian MMA promotion TKO where he is the lightweight champion. In the UFC Stout has posted victories over Spencer Fisher and Eklund while being defeated by Fisher and Kenny Florian.
Clementi (30-12-1 MMA, 3-3 UFC) last fought at UFC 79 is December topping rival Melvin Guillard via submission late in round 1. Clementi is currently riding a 4-fight win streak including another UFC win over Anthony Johnson. Prior to his recent back-to-back wins in the octagon, Clementi had mixed success in the UFC losing to Roan Carneiro, Din Thomas, and Yves Edwards with his lone win a submission victory against Ross Pointon.
Thanks to Trey Beall of Beat2Sleep for the info.