Where to go from 1st?

[BearsFan65]

12 team PPR league, full redraft, no keeper issues to consider. I've done well in this league in past years by winning the trade war, and am now in the "unfortunate" trading position of first place, overall points leader. My roster:

QB - Schaub
RB - Rice, Grant, Mendenhall, McCoy
WR - AJ, Megatron, Harvin, Breaston
TE - Gates, Celek
K - Akers
DEF - Vikings

The injury to Calvin (we'll see how that plays out) has me realizing that I'm one big hit away from having a pretty mediocre team. I realize I'm thin at RB, but Rice seems to get better each week, though I'm playing the matchups with Grant and Mendenhall this week.

What trade, if any, would you be trying to make to strengthen this roster? It's pretty clear that TE is where I have an expendable asset, but the position is so deep this year that I can't seem to get takers in a TE deal. I'm considering offering Celek for Kevin Walter (his owner has Carlson at TE). I've already had a Gates/Harvin for Gore deal rejected, no counter made, and this guy is seriously thin at WR. I could offer Gates/Grant, but would not offer Rice.

Does the Celek for Walter deal make sense for a little WR depth? Should I not go that route and keep trying to package for a stud RB? WHIR, thanks in advance.