From Tom Groeschen: Through Friday, CIN was 8-3, 2.64 when Hanigan started, and 1-8, 4.87 when Mesoraco started at catcher.
— Buster Olney (@Buster_ESPN) April 29, 2012
So, can we read anything into this? Everyone loves to beat up Dusty Baker for his penchant of playing veterans over youngsters, and many believe Mesoraco has All-Star potential, especially with the bat. He's hitting .300 with five walks in his small sample size of 30 at-bats, while Hanigan is hitting .283, but with just one extra-base hit and one RBI in 46 at-bats.
Of course, in one month, a few bad starts can skew a catcher's ERA. Here's a breakdown of the games each catcher has started:
Hanigan: Cueto 5, Latos 2, Arroyo 4, Bailey 1, Leake 1
Mesoraco: Latos 3, Bailey 3, Leake 3
It is interesting that Hanigan has caught all of Johnny Cueto and Bronson Arroyo's starts, meaning Baker has worked Hanigan with the more veteran pitchers and Mesoraco with the younger starters. So is Mesoraco's catcher ERA high because he's caught three of Mike Leake's four starts and Leake has pitched poorly? Or has Leake pitched poorly because Mesoraco hasn't helped? Does Cueto have a 1.39 ERA because Hanigan calls a good game, or because he's a good pitcher?
There is some evidence that Hanigan does make an impact behind the plate. Here are the ERAs of Reds catchers since Hanigan joined the team in 2009:
Hanigan: 3.97 ERA (687 innings)
Ramon Hernandez: 4.24 ERA (658 innings)
Mesoraco: 4.78 ERA (122 innings)
Hernandez: 4.80 ERA (732 innings)
Hanigan: 3.36 ERA (525 innings)
Corky Miller: 2.86 ERA (195 innings)
Hanigan: 4.27 ERA (670 innings)
Hernandez: 4.41 ERA (451 innings)
Craig Tatum: 4.32 ERA (173 innings)
Miller: 3.02 ERA (164 innings)
Catcher ERA isn't the whole story, of course, since it can be influenced by the pitchers each catcher works with, especially if certain combinations always work together. In 2010, for example, Bronson Arroyo had a 3.88 ERA and Hanigan caught 25 of his 33 starts, while Hernandez caught just two.
However, in this study by Max Marchi of Baseball Prospectus, Hanigan rated as the fourth-best catcher over the past four seasons in runs saved by his ability to frame pitches -- despite being only a part-time player.
So it's definitely possible that Hanigan is a superior defensive catcher, and that Baker is playing him more for this reason. It's also possible that Mesoraco will grow into one if he plays more.
It's important to note that Hanigan isn't a complete zero at the plate. He has little power, but does have a .370 career on-base percentage as he knows how to work walks. The defense and on-base ability do make him an underrated asset. I'm inclined to believe that Baker is making the right move by giving Hanigan more of the playing time, at least in 2012.