One of the things I noticed this season with Welington Castillo was that about any time he had an opportunity to make an error, he did. I'm not being serious of course, but it was pretty bad. Only 6 catchers made more errors than Castillo and he only caught 413.2 innings. It also seemed he allowed a lot of passed balls and wild pitches though when I looked that up toward the end of the season it was an example of my eyes telling me something that wasn't there.
Each year Matt Klassen has been measuring catcher defense for at least the last few years. It seems like longer than that and may actually be, but I'm not sure. The 2012 numbers are out now and they do show that not only was Castillo a poor fielding catcher, but so was most of the other Cubs catchers.
Out of 116 catchers, Castillo ranked 104th at -3.1 runs. He was behind the plate for 1828 plate appearances. Soto ranked 106th at -3.4 (1911 PA) and Clevenger ranked 109th at -4.0 runs (1786 PA). Oddly enough, Soto was actually very good with the Rangers. Overall he'd have ranked around 90th.
Soto, Castillo and Clevenger each caught roughly the same amount of time and were by ard far the majority of the season behind the plate for the Cubs. Those three totaled -10.5 runs.
Klassen's numbers don't include pitch framing or game calling, which is very difficult to calculate. It's possible that Castillo and Clevenger excel in these areas, but we wouldn't really know. It's more likely they're average at best and overall below average defensive catchers. Clevenger is a very poor hitter and considering his defense has little ot no value.
This actually surprises me a bit. His numbers were slightly better than Castillo's in the minor leagues and he has the platoon advantage at the plate more frequenly than Castillo. This isn't to say Castillo is an impressive offensive catcher. He's league average at best.
The Cubs don't have to spend much money behind the plate with these two, but it's worth wondering how much they could improve if they did spend a little bit. The free agent catchers don't offer a whole lot, but one might be available in a trade.