Well you just got shut out by this guy -
Hardball Dynasty – Fantasy Baseball Sim Games - Player Profile: Geraldo Oliva who isn't as good as Martin. Unless by lighting him up you meant putting him in the night's highlight reels.
For the record: Martin's P's - 81/65/63/38/23, Diaz 72/77/52/42/36. That difference is not "way worse". Martin's 1st and 3rd best pitchers are better than Diaz's - and carry more weight. You think I'm wrong, fine, show me your comp.
The C he's talking about dealing averages 103 RC over past 3 seasons and costs $6M/yr (don't forget he already has another very good catcher).
In exchange for Post - who is capable of 225 IP with a 4.25 RA and Martin - who is good for 4.00 ERA and 175 IP - at a combined cost of $720k. So you should also add to the equation whatever FA upgrade he can get for $5M.
I can see a team wanting either side of that trade due to their own needs but to say it's lopsided is pretty simplistic.