How good is J.T. Realmuto?

The All-Star catcher for the Miami Marlins remains the subject of trade rumors. While the Mets have reportedly agreed to a two-year deal with free-agent catcher Wilson Ramos, that still leaves the Dodgers, Reds, Rays and other teams involved in the Realmuto sweepstakes.

Realmuto hit .277/.340/.484 with 21 home runs for the Marlins in 2018, is entering his age-28 season and has two years remaining of team control. He has a good arm, with above-average caught stealing rates the past three seasons, including 38 percent this past season. He runs well, not just for a catcher but for any position, and has been a positive on the bases each of the past three seasons. He's coming off the best power numbers of his career -- he has increased his extra-base-hit rate from 27 percent in 2016 to 41 percent -- and may be even better in a different park, as he slugged .520 on the road compared with .444 at Marlins Park.

In short, he's very good, but to really understand the interest in Realmuto, we need to first examine the state of catching across the majors. Indeed, comments about the lack of good catchers right now in the majors -- especially catchers who can hit -- have not been exaggerated. Catchers hit a combined .233/.304/.374 in 2018, the lowest raw OPS figure since 1992. The OPS figure relative to league average was 87 (13 percent lower than average), the lowest figure since 2001 (86) and 2002 (87).

Just a few years ago, catchers collectively were almost league-average hitters. Check out the decline in OPS relative to average since 2010 (via Baseball-Reference.com):

2010: 93

2011: 95

2012: 99

2013: 96

2014: 97

2015: 89

2016: 91

2017: 94

2018: 87

Who was catching in 2012? Well, that was Buster Posey's MVP season when he hit .336 and won the batting title. Yadier Molina had his best offensive season, hitting .315 with 22 home runs (and finishing fourth in the MVP voting). Carlos Ruiz hit .327/.399/.542. Joe Mauer hit .365 when he was catching. A.J. Pierzynski and Matt Wieters put up good numbers. Jonathan Lucroy hit .318/.364/.508. Mike Napoli was still a part-time catcher. Miguel Montero had a good season with a .390 OBP. Russell Martin and Brian McCann weren't great, but they weren't terrible.

One thing you hear is that teams are placing a greater emphasis on pitch framing and thus more willing to play a good defensive catcher even if he can't hit. That may be true; it probably is true to some extent. That statement also sort of assumes that teams didn't pay attention to framing before it began to get quantified, which obviously wasn't true. Heck, we listened to Tim McCarver talk about the importance of framing for decades.

So maybe there's something to the framing argument -- after all, Jeff Mathis continues to get steady work. Just look at the group above, however: It got old. Only Molina was still an effective hitter in 2018, but Posey was injured, Mauer was a first baseman and Lucroy hit .241 with a .291 OBP. Meanwhile, the next wave of catchers didn't develop as anticipated: Carlos Santana was moved off the plate, Jesus Montero wasn't any good, Travis d'Arnaud and Devin Mesoraco battled too many injuries, and so on.

All that helped create the hitting nadir we saw in 2018. Maybe it was a one-year thing for catchers (after all, 2017 was in line with historical norms), or maybe it's a new level of expected production. Either way, it has made Realmuto very intriguing trade bait. In terms of WAR, he was clearly the best catcher in the majors in 2018:

Baseball-Reference

Realmuto: 4.3

Yasmani Grandal: 3.3

Buster Posey: 2.9

Willson Contreras: 2.8

Wilson Ramos: 2.7

FanGraphs

Realmuto: 4.8

Grandal: 3.6

Francisco Cervelli: 3.3

Contreras: 2.6

Ramos: 2.4

Complicating the Realmuto trade market is that Grandal remains a free agent. His value is hurt by his defensive problems in the playoffs -- he was eventually benched for Austin Barnes -- but he hit .241/.349/.466. His offensive game is a little different from Realmuto's: lower average and more walks, but the overall level of production is similar. He's two years older, but the public pitch-framing metrics at Statcorner.com rate Grandal as one of the best framers in the business.

The Dodgers still feel like the perfect match for Realmuto, although it's possible they bring Grandal back even though he turned down their qualifying offer. Two of their top prospects are catchers Keibert Ruiz and Will Smith and both played at Double-A last year. Ruiz is the better prospect, but he also just turned 20 in July. Realmuto would be the placeholder until Ruiz is ready, although he's probably a guy the Marlins are demanding as part of the trade.

The Reds make less sense as they have Tucker Barnhart signed through 2022. Of course, Realmuto would be a big offensive upgrade and they could flip Barnhart or just keep him as the backup (he'll make just $11 million the next three seasons).

The Rays already acquired Mike Zunino this offseason, but Realmuto would provide a creative way to upgrade the offense. They have a farm system that has the pieces needed to acquire Realmuto and they could presumably include Zunino in the deal.

The Brewers are certainly in need of catching help, currently relying on the tandem of Erik Kratz and Manny Pina. One team that hasn't popped up in trade rumors often is the Rockies, but their catchers hit an appalling .206/.307/.349. Chris Iannetta is still under contract, but he could become the backup (or flipped to give the Marlins a stopgap). The Rockies would probably have to part with top prospect Brendan Rodgers to make such a deal.

A final long shot: The A's need a replacement for Lucroy, who is a free agent. They're not going to trade pitcher Jesus Luzardo and would be hard-pressed to match the Rockies or Rays in prospects, so a return engagement with Lucroy is the more likely possibility (and prospect Sean Murphy isn't far away).

The Braves have Tyler Flowers and Brian McCann, but they could leverage their young pitching to make an upgrade on that pair.

Prediction: Realmuto is wearing Dodger blue before the new year.