2018 Arizona Diamondbacks Reviews: #21, Jeff Mathis

• 2018 rating: 5.23
• 2017 rating: 6.31
• 2018 salary: $2 million
• 2018 performance: 69 games, 218 PA, .200/.272/.272 = .544 OPS
• 2019 status: signed with Texas as a free-agent (two years, $6.25 million)

Jeff Mathis is the worst hitter active in the majors right now, and it isn’t close. His career OPS+ over 2,694 plate-appearances is 52. The next worst among players even to have 1,500 plate-appearances is Ryan Goins at an OPS+ of 64. Raise the criteria to two thousand PA, and there’s no-one bar Mathis below 70, with Billy Hamilton (70) and Alcides Escobar (73) the next worst, and the only men under 75. [As an aside, the latter list has three members of the 2018 D-backs among the eight lowest career OPS+, and four of the bottom 16, thanks to Chris Owings (#5), Jarrod Dyson (#8) and Daniel Descalso (#16). Also, Nick Ahmed comes in at #4 on the 1,500+ PA list. ]

Yet he was still one of the first free-agents signed this winter - and if he finishes out his new deal, will have as many MLB seasons as Hall of Famer Mike Piazza. Even though the contract signed with the Rangers covers his age 36-37 seasons, Jeff will net himself a nice 55% pay rise over the one he just finished with the Diamondbacks. There’s no secret about the reason for this: Mathis’s value does not come from what he does with a bat in his hands. It’s his skills as a catcher which matter. That’s both the obvious defensive skills of blocking pitches and throwing out runners, and working with the team’s pitchers, to call the game and also frame their pitches to best umpirical effect.

If you want evidence in support of Jeff’s value, look no further than Zack Greinke’s numbers. He has been with Arizona for three season, and each year has had a “personal catcher”: in 2017-18, Mathis caught 58 of Greinke’s 65 starts, missing only the games late in 2017 when Jeff had a fractured hand, and Chris Iannetta took over. In 2016, however, Greinke’s catcher was Welington Castillo, whose defensive reputation was... not good, shall we say. Over these three seasons, we have the same pitcher throwing in the same part, just to a different catcher [There was the humidor this year, I admit]. If you look at the numbers posted, you can see what could be Mathis’s impact.

The difference between Mathis and Castillo appears dramatic. About seven-tenths of a run reduction on ERA, sixty points of OPS down and, perhaps most emphatically, a better than 50% improvement in Greinke’s ratio of strikeouts to walks. If Greinke’s much-improved value these last two seasons is indeed significantly a result of throwing to Mathis, then finding a replacement becomes a priority. Either that, or the team needs to trade Greinke this winter, because his value is only going to decline when he starts throwing to NotMathis in 2019.

It’s harder to be sure if he had the same impact on our other starters, because Mathis started more games with Greinke this year, than with everyone else in our rotation put together. But it is worth noting that Patrick Corbin also pitched a LOT better after Mathis came on staff. And in both those seasons, Corbin’s ERA was far better throwing to Mathis than other catchers. Overall, across Patrick’s 18 starts in 2017-18 with Jeff, his ERA was 2.33; with everyone else, it was 4.03. With Corbin a free-agent, it will be interesting to see how he fares without Mathis, wherever Pat ends up signing.

With hindsight, the D-backs signing of Mathis in December 2016 seemed almost inevitable. Both manager Torey Lovullo and pitching coach Mike Butcher had seen Mathis in action, in Toronto and Anaheim, with Butcher having known the catcher almost since Jeff was drafted out of high-school in 2001. Dan Haren, hired the same week the team signed Jeff, had the previous March called Mathis, the “best catcher I threw to in my 13 years in the big leagues.” But the key was perhaps Arizona’s new director of research and development, Mike Fitzgerald. He brought with him from the Pirates a strong belief in framing as a skill - and just a few days later, Mathis was a Diamondback.

This aspect of the catcher’s game was at its strongest this year. Despite making only 61 starts, per StatCorner he led all MLB catchers in framing runs saved, at +14.1 above average. Baseball Prospectus had Mathis slightly less valuable, but still said he was worth +11.8 runs. Averaging those two, and going by the rough rule of thumb that 10 runs = 1 WAR, Mathis’s framing alone was worth 1.3 wins last year - something not included in bWAR. Add that in, and he goes from barely replacement (0.2 bWAR), to sixth-best among our position players, with those ahead all having appeared in at least fifty more games than Mathis. His $2 million cost suddenly seems a bargain.

As such, it was a very quiet and understated performance. There are no video highlight reels to be found on MLB of great Mathis frame-jobs, but the clip above. from a September 11 game against the Rockies in Coors, is perhaps a good example of what Mathis can do. A Greinke pitch is clearly outside, but with a barely perceptible twitch of the wrist, Mathis brings the ball back to give home-plate umpire Fieldin Culbreth the proverbial “good look” at it. Good enough look, certainly, and Ryan McMahon is left to trudge back to the dugout, carrying his bat. [Worth noting: Greinke’s strike looking percentage also rose under Mathis. It was only 24.8% throwing to Castillo in 2016, but was 30.1% this year]

Of course, we should acknowledge how appalling Mathis was as a hitter. He leaves Arizona with a line of .207/.274/.297, for a .571 OPS over his 421 PA here. Only one position player in franchise history with as many PA, is within 75 OPS points of being that bad (fellow catcher Rod Barajas put up a .591 OPS over 553 PA). But it’s fair to say, we expected little different, given his career OPS was .562 when we signed Jeff. He was who we thought he would be at the plate, yet may have taught us something about where catcher value lies. We may know more when we see how the pitching staff does in his absence next season.