The season has reached its midpoint, so this seems like a good time to take a look at some rankings. I debuted here at Baseball Prospectus with a series on evaluating catchers defense, so catchers are the subject of the top-10 list that follows.

The catchers will be listed with four numbers beside their names. The first three cover batting, baserunning, and defense. The fourth is the sum of the numbers pertaining to each of those areas.

The figure used for evaluating the catchers’ bats is BRAA, which measures the number of runs produced relative to the average hitter, with parks taken into account. Performance on the basepaths is assessed with Base Running Runs (EqBRR), which you can find in our sortable stats: as you know, BRR quantifies all aspects of baserunning, from stealing bases to taking the extra base both on hits and on outs.

My previous work on catcher defense is behind the third number, adding together evaluations of each backstop’s ability to field batted balls, control the running game, prevent passed balls and wild pitches, and practice the undervalued art of framing pitches.

Here are the 10 most valuable catchers of 2012, with stats updated through June 30th.

#10. Martin Maldonado 1.6; 0.4; 6.4; 8.3
With injuries afflicting both Jonathan Lucroy and George Kottaras, the 25-year-old Maldonado has found some playing time in Milwaukee and did a good enough job to get onto this list. Maldonado’s 7.2 framing runs make up most of his value. As a cautionary note, the algorithm I use for these rankings does not take the ballpark or the pitching staff into account*; since Lucroy is also ranked very high in framing, one of those neglected factors might be playing a role.

*The algorithm I used for the articles at the beginning of the season did account for pitchers, but that method is too computer intensive to be used on a frequent basis. However, the quicker version gives results consistent with the slower one.

#9. Jarrod Saltalamacchia 7.2; -0.8; 2.4; 8.7
Salty is making $2.5 million this year and is in the top 10 thanks to his career-best offensive season, as he has already matched his home run total for 2011. On the fielding side, he is below average in blocking, fielding batted balls, and preventing the running game. However he has solid framing numbers (7.9 runs saved) that drive his defensive value well over to the positive side.

#8. Joe Mauer 11.6; -1.0; -0.1; 10.5
Mauer has played half of his games as either a DH or a first baseman. However his offensive numbers have been at their best when playing behind the plate (.341 TAv as a catcher, .272 when playing elsewhere), so it’s fair to keep him on this list. On the defensive side of the game, Mauer manages to be average by compensating for below-average fielding and preventing steals with above-average blocking and framing.

#7. Ryan Hanigan 0.0; -0.4; 13.0; 12.6
Hanigan is a solid defensive catcher, with above-average ratings at everything except fielding short batted balls.

#6. Brian McCann -5.8; 0.6; 18.0; 12.8
When you’re enduring your worst offensive season and you’re still the sixth-best catcher in baseball, you must excel in other areas. McCann’s peripheral offensive stats are on par with his career rates (fewer walks, but also fewer Ks), while his BABIP is off the charts in a bad way (below .230). His batting figures should improve by the end of the season, at which point he figures to be close to the top of this list.

McCann’s defensive line is the second best so far, driven mostly by 16 framing runs. His numbers for preventing steals and wild pitches/passed balls are also above average (another couple of runs saved between them.)

#5. Russell Martin -1.4; 0.4; 14.9; 13.8
Not only are the Yankees getting their offensive output from other positions, but you shouldn’t regard the negative value of Martin’s offensive output as something particularly egregious. These BRAA figures compare catchers with all other players, so you should expect many of them to rate as below average. Depending on playing time, the positional adjustment at this point in the season is around 2-3 runs for catchers.

Martin, who does so well in the defensive parts of his job, began his pro career as an infielder.

#4. Buster Posey 15.0; -1.2; 11.2; 25.0
The bat is what separates the elite catchers from the rest, as the difference between the fourth and the fifth catcher is roughly the same as that which separates the fifth from the 17th. Posey’s has been the second-best bat in baseball among his peers so far, and the Giants desperately needed it back in the lineup.

#3. Yadier Molina 14.7; -2.1; 13.4; 27.9
The Cardinals’ catcher comes with the full package (except running, of course). He is currently one of the best bats in Mike Matheny’s lineup, and he is above average in all four defensive elements I considered. Molina has saved 9.7 runs with his framing, 0.2 via fielding batted balls, 1.4 by preventing pitches to pass by him, and 2.0 by gunning down potential base stealers. The last figure is all the more impressive when you consider that his reputation vastly reduces the opportunities he has to put his arm to use.

#2. Jonathan Lucroy 9.9; -0.5; 20.8; 30.1
Some skepticism about Lucroy’s line is in order. The Brewers’ catcher was sidelined by an injury that required surgery on his right hand when he was having a good offensive season; however, his numbers were highly inflated by an unsustainable .381 BABIP. On the defensive side, his off-the-charts 21 runs saved from pitch framing, while corroborated by a good rating in 2011 as well, seem overly optimistic.

#1. Carlos Ruiz 24.3; -0.4; 9.9; 33.7
Carlos Ruiz hit a very respectable 17 and 13 runs above average in 2010 and 2011, respectively. In 2012, he’s head and shoulders above his previous seasons and among the top 10 hitters in BRAA, due in part to a .365 BABIP which is likely to regress as the season continues.

Unlike other catchers in this list, his 10 runs saved on defense do not entirely derive from his framing skill. In fact he is very well balanced in the four areas explored here and ranks as the best at fielding balls in play, with 3.3 runs saved, way in front of runner-up Chris Snyder, who sits at 2.0.

Honorable Mention: #11. Jose Molina -3.7; -1.2; 12.6; 7.6
Just outside of the top 10 sits the poster boy of my previous articles. When the season started, I maintained that the Rays had gotten themselves a good bargain by inking Jose Molina for one year at $1.8 million. The low price was due to the fact that his most valuable assets are the ones that are most difficult to quantify. It’s not a coincidence that he was grabbed by one of the clubs most willing to embrace advanced statistical analysis. Our own Ben Lindbergh went as far as writing that Mike Fast’s and my works on pitch framing might have led to Jose’s move to Tampa Bay. If you read Jonah Keri’s Extra 2%, you’ll probably understand why that’s not unlikely.

As a starting catcher, Molina has already amassed 15 runs saved with his framing ability. Most notably, he helped Fernando Rodney strike out Cody Ross for the final out of an April game at Fenway, prompting the Boston outfielder’s flip of the bat and smash of the helmet. But fans will more likely remember his framing (again in the ninth inning of a one-run game) of Brett Lawrie, who slammed his helmet at the ump’s foot.