The news contradicts a report from September where Mark Ruffalo revealed he would not only portray Bruce Banner, but the motion-captured Hulk component of his character as well. Here is Mark Ruffalo's statement from September:
It seems that plan for Mark Ruffalo to put on the CGI suit has been scrapped. It is possible that Brandon Molale could be playing the CGI Hulk's stunt double for all the big action set pieces, with Mark Ruffalo also performing as the CGI version of the Hulk.
Marvel's The Avengers was released May 4th, 2012 and stars Robert Downey Jr., Chris Evans, Mark Ruffalo, Chris Hemsworth, Scarlett Johansson, Jeremy Renner, Tom Hiddleston, Clark Gregg. The film is directed by Joss Whedon.