It wasn’t all that long ago that Joe Mauer was getting booed at Target Field. I was in attendance during the finale of the team’s first home series of the year when he was jeered heavily after failing to drive in a runner from third base in two straight at-bats.

In his next at-bat, he homered.

And that’s been the theme of the season for Mauer. The hometown star from St. Paul who was placed on a pedestal by many fans after winning the first of three batting titles suddenly became the target of those same fans’ frustrations.

Whether or not you believe that the bilateral leg weakness that sidelined him last year was legit or not, the 2011 season was a strange one for him. Injuries are nothing new to Mauer, but in just 82 games last season, he posted career lows in batting average (.287), on-base percentage (.360) and slugging percentage (.368).

Minnesota Twins catcher/first baseman Joe Mauer is hitting .329 this season. Associated Press photo

But Mauer has bounced back in a pretty big way in 2012. His 1-for-3 effort on Thursday left his batting average at .329 for the season. He has six homers this season, which isn’t much. But three have been hit at Target Field, where Mauer had hit only one career homer coming into this season.

His OBP is a league-leading .415, putting his OPS at .870.

The big question is: Is Mauer earning his keep? After signing an eight-year deal worth about $23 million per season entering 2011, is his performance justifying the salary?

Last year, it certainly wasn’t. But this year, you might be surprised. FanGraphs.com, which tracks a player’s value in terms of dollars, has Mauer’s current 2012 production worth $13.6 million already this season. And that number is only going to go up.

If he remains healthy, he might actually end up at $23 million when the season is over. And I’m pretty confident that number takes into account that he’s only made about half of his starts at catcher.

But even just sharing duty at catcher, Mauer’s value as the second-best hitter in terms of average in the AL can’t be overstated. After all, the average big league catcher this season is hitting .247 with an OBP of just .315. Mauer has that last number beat by 100 points.

The Twins have been bad this year. You can blame management for not drafting and developing enough young pitching. But you can’t blame Mauer … at least, you can’t blame him too much.

REVISED: Thanks to “RC” for reminding me how I should not go strictly off memory when blogging. Details early in post are cleared up.