Green was a good punt returner in college but has flopped in the NFL. Green hasn't returned a kickoff since 2006. He averaged a pitiful 19.7 per kickoff that year. He returned 9 punts last year for an average of 4.2 yards per return.
Just for comparisons sake, Pierre Thomas averaged 25 yards per return for us last year, and noone is going to accuse him of being anything more then an average return man.