Seyfarth is holding the #13 until he gets beaten out by the higher quality players like Lualili'i & Fa'agutu.
They are just not ready right now.
Consider Seyfarth a place holder & hope that the young guys development is fast.
Guys like Seyfarth hold value in a club. Work & train hard, have the occasional good game in them. At some point in the season, these guys get asked to play a role & help the team to not lose. You just need him to be #18-#20 in the pecking order, not in the top 6 forwards we run out.