UFC 136: Why did Melvin Guillard leave Jackson's MMA to go train with Rashad Evans?

Source: http://www.mmamania.com/2011/10/3/2465835/ufc-136-why-did-melvin-guillard-leave-jacksons-mma-to-go-train-with

Marvin Eastman  Stav Crazy Bear Economou  Yves Edwards  Justin Eilers  Jon Olav Einemo Per Eklund Jason Ellis Aleksander Emelianenko Fedor Emelianenko Yasubey Enomoto