Should the Arizona Diamondbacks extend Welington Castillo?

According to Jack Magruder, the Diamondbacks have been having internal discussions with regard to signing Welington Castillo to a long-term contract extension. Castillo is currently in his second season of arbitration eligibility, so if no action is taken, he will hit the free-agent market at the end of the 2018 campaign. Would it be a good idea to lock Castillo up for additional seasons?

The case in favor

Welington is already the fourth most-productive catcher in team history, having put up 3.1 bWAR since his arrival from Seattle in the Mark Trumbo trade, in June last year. Much of that has been a result of Beef’s bat: in 162 games for the Diamondbacks through Tuesday night, he had hit .260 with 29 home-runs, for an overall 105 OPS+. That’s the best figure among the 11 catchers in Arizona history with 200 or more plate-appearances, just edging out Miguel Montero’s OPS+ of 103.

Defense was always seen as Castillo’s weakness, but there are some indications that he has been improving in this area. Using the StatCorner.com report on pitcher framing, Welington was rated as one of the very worst in 2014, costing his team 24.3 runs with his work behind the dish, compared to the average catcher. Last year, he was still bad, but not as bad; his impact dropped to -10.9 runs. And in 2016, he has improved again, to the point where Castillo is marginally better than average (+0.5 runs). He has been better at throwing out base-stealers too; his 34% rate this year is a career-high, and significantly better than MLB average (28%).

Locking Castillo up would also solve the problem of the D-backs’ weakness at the catcher’s position in their farm system. Unless you think Chris Herrmann, Tuffy Gosewisch or Oscar Hernandez can be everyday catchers, there aren’t many alternatives beyond Welington, and those listed all have significant question-marks. Herrmann has been great this year, but is still a career 69 OPS+ hitter; Gosewisch is even lower, and Hernandez has only 20 games experience at the major-league level, so is far from a sure thing. Beyond them, we don’t have a catcher with meaningful playing time above High-A, posting an OPS of even .700.

The case against

This can be summed up in two words: past history. The Diamondbacks have fared poorly with previous catchers given contract extensions, and those should stand as a warning when it comes to considering the same thing for Castillo. Let’s take a look at the two most well-known examples.

Chris Snyder: three years, $14.25 million. In December 2008, the 27-year-old Snyder had just finished his best year as a Diamondback, putting up a 103 OPS+ over 115 games, and being worth 1.8 bWAR. This deal bought out his last two years of arbitration and his first of free-agency. However, he was unable to stay healthy, for a variety of reasons, including a fractured testicle resulting from a foul tip. [I’ll pause for male readers to shuffle uncomfortably] He appeared in only 200 games over the three-season period of the extension, and was worth a total of 0.7 bWAR. Snyder was salary dumped on the Pirates at the trade deadline, with half a year left on his contract.

Health is a very real problem for any catcher. No position on the field gets beaten up to quite the same extent, and catchers tend not to age well. That matters, because Castillo is significantly older than Snyder, having turned 29 in April. Any additional years of control would be for his age 31 and later seasons, and since 1998 just eight catchers have been worth even ten bWAR from that point on in their careers. I’d be very wary of the team doing more than looking to add, at most, two years of control for Welington.

Miguel Montero: five years, $60 million. This extension occurred in May 2012, and is likely the poster-child for why giving long-term extensions to catchers can be a disaster. The situation seemed not dissimilar for Arizona to the current one, reports at the time citing “The possibility of losing [the player] to free agency and the lack of an alternative.” Montero had been an All-Star the previous year, and also received MVP ballots. This one started well enough for the Diamondbacks, Miggy matching his 2011 bWAR of 4.1 in the first season, and receiving further MVP consideration.

However, the contract signed actually covered the years 2013-2017, and Montero’s performance basically imploded as soon as it kicked in. We still have a year and a couple of months to go, but so far, that $60 million has been repaid with only 1.6 bWAR. Much like Snyder, Miggy was salary-dumped, being dealt to the Cubs in December 2014, for Zack Godley and minor-leaguer Jeferson Mejia. Ironically, he was initially sharing catching duties there with Castillo. To date, Montero has cost the Cubs $26 million and been worth 0.8 bWAR in his age 31 + 32 seasons.