Seahawks RB Christine Michael’s shortcoming is two-fold: the concern about his ability to block and his lack of participation in special teams (again, not because he refuses to do it, but because the opt for someone else). For the amount of times he would carry the ball, it didn’t make sense most of the season to have him gobble up an active roster spot if he couldn’t also play special teams.
One other good thing about Michael finishing last season with only 18 carries: he finished the season with only 18 carries. Protecting the body of a running back for a whole year in the NFL holds its own value. If the Seahawks decide they can’t swallow Marshawn Lynch’s 2015 cap hit and Michael has proven after more chances in 2014, which seems will be the case for him, he can take over, then they bought themselves almost two full years to work him in.
Lynch is signed through the 2015 season, so he could continue to be the RB1 through next year. His hefty cap number will make him a cut candidate if the team thinks Michael is ready to carry the load.