What value does a TE have in trade?!

[JMinn1087]

Alright, alright i got a bit of a dilemna here. Im in a 10 team standard scoring, that has 2 RB slots, 2 WR's and a Flex WR/RB spot, its a H2H league and i have two solid TE's and im trying to move one to upgrade at a position but am not sure how much i expect in return for my player here's my lineup:

QB: Brady, Cutler
RB: Adrian Peterson, Ray Rice, Kwoshon Moreno, Felix Jones
WR: Calvin Johnson, Chad Ochocinco, Torry Holt, Donny Avery, Steve Smith (NYG)
TE: Jason Witten, Chris Cooley
DEF: Chicago
K: Longwell

I believe i have a strong team as of now but would like to upgrade at RB or WR and am willing to trade Witten. What can i expect to get for Witten or Cooley if i move him. Im thinking a 2nd tier RB or WR (wes welker is who im trying to get) but can i get advice as to what my teams weakness is and what value i can expect. Thank you and i will help you in return.

[JMinn1087]

just some advice would be helpful, and ill do the same

[FirstAnd99]

I usually try to package TEs in deals...For instance, your good TE (Witten) for his crappy TE. And your crappy RB for his good RB (or WR)