The idea of a cost-controlled left-handed hitting catcher who is willing to stand mostly motionless in the batter's box while pitchers hurt themselves and the rest of the defensive team with their wildness is a great one. Silly pitchers. Just throw strikes you big sillies! In that vein, it's great that the Seattle Mariners acquired John Jaso and/or a John Jaso-shaped object. However, Jaso arrives in Seattle with a bit some uncertainty around his offensive talent. Hopefully he didn't check that uncertainty through on his flight here. Baaaaaag fees, yeah?
The 2010 version of John Jaso is the neater of the two more recent versions with the decent batting average (.263) and the 59 walks to just 39 strikeouts. That's the one to ask Santa for. This most recent 2011 campaign was more explanatory of how Jack Zduriencik managed to spring Jaso for a current Quad-A relief pitcher. As fans of the Mariners baseball club it takes far less than a .224/.298/.354 batting line to make us pessimistic and abandon all hope for any shred of happiness, ever. About anything. However, could it be feasible, could it be possible, that deep within the bowels of the Marauder there is a festering wound of sunshine? Good question, mysterious fellow future traveler! How have you been dealing with The Misfortune?
You're right though, there is an attainable possibility of improvement. Dave Cameron categorized hitters by three measures, isolated slugging, swing rate and contact rate. Those three roughly correlate to what we usually think of as the primary hitting skills of power, discipline and, well, making contact. Cameron isolated and laid out the individual hitter seasons that were kindred to John Jaso's career numbers. The bad news is that 2011 Jaso shows up with the worst wRC+* of the bunch. The Christmas lightsy good news is that BABIP appears to be the prime driver of success and BABIP can be fickle over a single year. Jaso is surrounded by company that exhibited normally higher ball in play averages (a big weakness for Jaso last year) and resultingly higher wRC+s.
wRC+ = weighted runs created, relative to league average where 100 = league average.
Typically, hitters in Jaso's group hovered around league average on offense which, for a catcher, would be brilliant. I ran a corresponding check using the standard deviation of the three categories as the cutoffs and came to a similar conclusion as Dave. Also, these are all lacking park adjustments and while that shouldn't muck with the results too much, it's even more enthusing that Tampa's ballpark seems to promote strikeouts while reducing walks and extra base hits to left-handers. Yay!
As it turns out, Jaso's career wRC+ is 101, so there's that. More of that would be swell, John. I recommend you (you you, not John) go read Dave's piece for the full list of qualifications and disclaimers as there is subtlety that I am skimming over here. If you need an ultra short version, take 2010 Jaso and 2011 Jaso, split the difference and call it your projected 2012 Jaso.