The problem isn't when Fusitu'a plays, its the number of games he misses. He's missed over half the games played since he arrived. If he was an absolute megastar when he played we could maybe live with it, but he isn't, he's an above average winger who is plus to the team but not irreplaceable.
Frankly if Roberts is just not really noticed, then that's OK for now, as it means he's not dropping clangers (see Olpherts) or just being infuriating (Tindall). He'll either improve and keep his spot longer term or get replaced. He's probably not at all a bad squad player though as he can cover wing or centre fairly reliably.
