Essentially, March will start in the games where we need a left winger to protect our left back. Gross will start every game he's fit enough to play and we don't really have a back up option for him unless we're going to unleash Propper further up the pitch (and we've seen no sign of it so far).
Right now, he looks like a donkey. But come the end of the season I do think he'll have helped himself to at least 5 goals and once he's nabbed a place in the team, I think he'll keep it and not look back.