Our own Jordan Gorosh wrote up a comprehensive scouting report on Andy Oliver a few weeks ago, which can be found here. Basically, Oliver has tremendous raw stuff, a power arm, absolutely zero command, and a tendency for bad mechanics. We've seen him in Detroit on a few occasions, usually walking people, but the hope was that he would be able to harness his mid-to-upper 90's heater enough to become the left-handed power starting pitcher that the Tigers have lacked. Late in 2012, Oliver shifted to the bullpen, where many scouts (myself and Jordan included) believe he would have his best chance at success.
Ramon Cabrera, the catcher who the Tigers got in return for Oliver, just turned 23 in November and spent most of 2012 with Class Double A-Altoona of the Pirates organization. I have yet to see Cabrera in action, so I'll give you guys what I know about him based off of a compilation of other reports. He's a short, stocky-framed guy at 5'8", 200, but is actually not a bad athlete for someone of his build. He has excellent plate discipline, walking at a 9.1% clip in 2012, while striking out at only a 10.3% clip. He has a short, compact line drive swing that is good for moderate gap power, but he has well below-average HR power, and shouldn't be expected to hit any more than 10 or so at the most. He's an improving defender that projects to at least be average behind the plate with average arm strength, making him a pretty valuable player.
The kicker is that he is a switch hitter, with no real notable R/L platoon splits, meaning that he should be a valuable backup catcher in the major leagues, regardless of if he's facing a RHP or a LHP.
As I said, he spent most of 2012 at Double A, so the Tigers may decide that he needs to spend some or all of 2013 at Triple A-Toledo to further refine his game, but I'd expect him to be given every opportunity in Spring Training to win the backup catcher job, where Bryan Holaday is currently penciled in.