When a 27 year old player's numbers are lower than their career average that means they are in a slump. Brandon Bass has proven throughout his career that he is one of the best isolation defenders and mid range jump shooters in the league. This is very important because the athleticism of the Heat make it necessary to switch when guarding Lebron.
http://redsarmy.com/2012/10/22/the-case-for-starting-brandon-bass/The best big that we can reasonably trade for is Marcin Gortat. I hate to burst people's bubble here, but Gortat would do absolutely nothing to help against the Heat.
March 20th, 2012 matched up against Dexter Pitman and Chris Bosh:
Gortat 13 points in 6-13 shooting. 8r 1a 1b for a -7
Pittman and Bosh combined for 15-22 for 35 points and a combined +21.
November 17th matched up against the much smaller Bosh and Battier:
Gortat 4 points in 2-5 shooting. 6r 2s 1b for a -11
Bosh and Battier combined for 13-19 FG for 24 points and were a combined +35.
The first game he had Steve Nash feeding him the ball and the second had Goran Dragic so he was playing with excellent point guards.
Unless you happen to have a trade for Dwight Howard or Marc Gasol type player there is no center that is going to dominate the Heat. More likely they would stand around and let Battier and Bosh drain 3 after 3.
The Celtics on the other hand took the Heat to 7 games playing small with Ray Allen, Marquis Daniels, Sasha Pavlovic, Mikael Pietrus, Greg Stiemsma, Ryan Hollins and Keyon Dooling.
Avery Bradley, Jason Terry, Jeff Green, Jared Sullinger, Courtney Lee, Chris Wilcox, Leandro Barbosa are an upgrade in every position.
If you want to beat the Heat you need athletic players who can contest the 3 and make life difficult for Lebron and Wade if forced to switch. That is Lee, Green and Bass. Trading 2 or three of these guys for a 7 footer who will be forced to sit in the bench because they are useless against the Heat is a sure fire way to lose to them.