PITTSBURGH -- The Pirates are officially in the market for a catcher after non-tendering Elias Díaz, once viewed as the club’s backstop of the future, before Monday’s 8 p.m. ET deadline to offer contracts to their arbitration-eligible players.

The Pirates did tender contracts to eight players: Keone Kela, Michael Feliz, Josh Bell, Adam Frazier, Jameson Taillon, Trevor Williams, Joe Musgrove and Chad Kuhl, and they avoided arbitration with infielder Erik González by agreeing to terms on a contract for next season.

The decision to non-tender Díaz comes as somewhat of a surprise, only because of the Pirates’ lack of Major League-ready depth at catcher. With Díaz gone, Jacob Stallings is the only catcher on the club’s 40-man roster. Díaz, eligible for arbitration for the first time, was projected by MLB Trade Rumors to earn $1.4 million next season.

But Díaz, 29, is coming off a terrible year at the plate and an even worse season behind it. After dealing with a mysterious virus in Spring Training, he hit just .241/.296/.307 with two homers in 332 plate appearances; his Wins Above Replacement value was minus-1.3. According to Baseball Prospectus, he ranked last out of 113 catchers in Adjusted Fielding Runs Above Average. By the end of the season, most of the Pirates’ starting pitchers had asked to work with Stallings.

It was a stunning step back for Díaz, who seemed to come into his own as Francisco Cervelli’s backup in 2018 after several years spent shuttling between Pittsburgh and Triple-A Indianapolis. The Pirates’ No. 9 prospect in 2016, Diaz hit .286 with a .792 OPS and 10 homers in 277 plate appearances and totaled 1.6 WAR in ’18.

Stallings delivered a promising performance in some regards this past season, showing more power and grading out among the Majors’ better defensive catchers, so perhaps he is poised to take on a more prominent role. Still, Pittsburgh must acquire another catcher this offseason to pair with Stallings; the Bucs have no catchers among their Top 30 Prospects, according to MLB Pipeline.

If Stallings is the primary catcher, he’d have a chance to be the club’s first homegrown Opening Day backstop since Ryan Doumit (2008-11). The Pirates spent the past decade relying mostly on a series of former Yankees backups to fill their need behind the plate, from Russell Martin and Chris Stewart to Cervelli.

The market for catchers this offseason has been more active than any other position, but there are some proven options still available in free agency. Martin, Robinson Chirinos, Jason Castro and Austin Romine are among the top catchers who remain unsigned.

González, who spent most of last season on the injured list, is set to return as a utility man next season. The 28-year-old hit .254/.301/.317 with one home run and six RBIs in 156 plate appearances during his first year with the Pirates. He also played four positions, spending most of his time at shortstop and third base.