Me and another manager in my league have been trying to make a trade to no avail, and I was hoping that some people here on the forms could kind of act as a mediator to put up some hypothetical offers that we could use as a starting point.

Here is his roster, mine is in my signature.
C: Krejci, Desharnais, Roy, O.Jokinen
LW: Parise, Eriksson, Semin, Mcdonald
RW: Perry, Neal, MSL, Sharp
D: Letang, Buff, Chara, Green, Yandle, Suter
G: Rask, Niemi
Bench: B.Boyle, Okposo, Ellis, Backstrom, Khudobin
Farm (4): Granlund, Grigorenko, Coyle, Niederreiter

I am looking to acquire a defenceman (let's say Letang for simplicity) and he wants a centerman.

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TWALL
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10 Team Keeper League (Keep 12 & 3 Minors), Weekly Lineups: 4C, 4LW, 4RW, 6D, 2G, 6B, 4Minors
Categories:
G,A,P,+/-PIM, SOG, FOW, GWG, PPP, SHP, HIT, Blks, ShG, SGWG,
GS,W,GAA,SV%,SHO

Center: Tavares, Toews, Spezza, Kesler
Left Wing: Lupul, Lucic, Dupuis, Dubinsky
Right Wing: Kessel, Gaborik, Vrbata, Brouwer
Defence: Bieksa, Robidas, Girardi, Coburn, Schenn, Souray
Goalie: Price, Anderson
Bench: O'Reilly, Fleischmann, Setoguchi, Timonen, M. Stuart, Lehtonen
Minors: Kreider, Kassian, Nyquist, Killorn
IR adds: Smith, Glencross