I'm with this line of thinking but I"m guessing Fredericks moves on (just based on how things seem to work, not any inside knowledge). My thoughts on Strickland are these:
1. He has shown you essentially nothing this year. Yes, OL has been an issue and it's first year in the system and he's a young back. All of those could be factors. Having said that, really haven't seen anything from him that makes you optimistic.
2. Young kids play at RB all the time -- even if you like Strickland's potential there, is there a decent chance you could upgrade with a younger player? Seems like the answer could be yes.
3. Could Strickland -- even if you more or less like him at RB -- potentially help you out more somewhere else? WR or DB? I always think of tebucky jones who was a phenomenal athlete but was only solid at RB. Meanwhile, he plays one year at safety and basically plays at an All-American level and goes on to a strong NFL career. RBs need talent but above all they need to be RBs. Not sure Strickland is.