I spotted Josh Thole playing catch before Tuesday night’s game using a regular fielder’s glove, so I asked him about it. He dismissed it as something he used for fun in warm-ups and said he didn’t think it helped or hurt or affected his catching at all. So no story there.

Thole called his defense “a work in progress.” “There are growing pains,” he said. “But it’s coming along.”

After an encouraging 2010 campaign, Thole’s work behind the plate in 2011 has shown more growing pains than progress. Until recently, he struggled to throw out basestealers. He sometimes appears to stab at or try to backhand pitches in the dirt, rather than block them with his body. He leads the league in passed balls, though part of that is due to being charged with handling R.A. Dickey’s knuckleballs every fifth day.

Citing batters who claim that swinging at a knuckleball screws with their timing against conventional pitchers, I asked Thole if he thought catching the knuckleball might affect his handling of the rest of the staff.

“Not at all,” he said. “The stance is a bit different, but it’s all the same thing.”

So nothing there, either.

Defense is tough to quantify, especially behind the plate. Beyond the Boxscore takes crack at it by assigning run values to catchers’ errors, passed balls, wild pitches allowed, and stolen-base rates relative to the league averages. As of July 19, Thole ranked 91st of 94 big-league catchers in 2011.

Granted, part of that is because he serves as Dickey’s personal catcher, a task that inflates his number of passed balls and wild pitches allowed. Also, Thole has thrown out a handful of runners in the past week, and since the stolen-base rate stat inherently deals in relatively small numbers, the recent run of success is probably enough to lift him up a bit in that category.

And it’s worth noting that in 2010, Thole’s defense rated as above average by the same methodology. It seems likely that the fluctuation has more to do with the innate finicky-ness of defensive metrics than Thole actually getting worse, and his actual level of ability behind the plate — by stats or otherwise — lies somewhere in between: passable, but not great. His struggles this season, though real, have not come with such an alarming frequency to forebode further or worse problems moving forward; even struggling, he is within the range of Major League catchers

There’s more to catching than blocking balls and throwing out runners, but for as much as pitchers talk about their batterymates’ game-calling, it’s difficult to find any evidence that any one catcher is better at it than any other. It seems possible and even likely that some catchers work better with some pitchers, but if you look at teams’ ERA splits by catchers from year to year, you’ll see there’s no real pattern to it.

Pitchers throwing to Thole in 2011 have yielded a slightly higher ERA (4.14) than pitchers throwing to Ronny Paulino (3.94), but Thole boasted a better catcher’s ERA than Rod Barajas in 2010 and the memorable Brian Schneider/Omir Santos tandem in his small sample in 2009. It’s not a stat worth investing much time or space in (whoops).

Offensively, Thole has also taken a step backwards this year after a promising half-season in 2010. Though he has not completely collapsed, his numbers are down across the board in 2011.

Still, the largest possible body of evidence for Thole — 166 games now — shows a 24-year-old catcher with a career .271/.350/.347 hitting line. That’s a hair better than the league-average .243/.315/.380 mark for Major League backstops in 2011.

Thole hits for almost no power, so he’ll never maintain that aspect of the Mets’ catching tradition. But there’s a lot to show he can hit like at least an average big-league catcher, if not a touch better. He’s 24, after all, so he’s probably still improving.

Around the trade deadline, talk spread that the Mets could be looking to upgrade behind the plate, and it seems likely the same discussion will resurface this offseason. And indeed, Thole is not now and does not look apt to ever be a great catcher on either side of the ball, so it’s a position at which the Mets could feasibly improve.

But Thole is young, under team control through 2016, and a left-handed hitter — especially valuable at a position that demands some form of time-share. So I question the logic of dedicating much of the team’s offseason resources to a spot at which it has what appears to be a viable and inexpensive if unspectacular Major Leaguer. Not when they have a shortstop to re-sign and need pitching help like they do.

I’d chalk up Thole’s 2011 to growing pains, like he said. Sometimes it’s difficult to stay patient through the struggles, but it’s important to remember that not every young player hits the big leagues and starts consistently producing like David Wright did. There’s a growth curve, and Thole should still be on the front side. This is what this season is for.