OAKLAND -- The A’s decided against tendering contracts to Blake Treinen, Ryan Buchter and Josh Phegley on Monday, making all three free to sign with another team as free agents.

The rise and fall of Treinen was rapid in his three seasons with Oakland since arriving from the Nationals via trade in 2017. The right-hander took over as the club’s primary closer in 2018 and put together a historically dominant year that saw him post a 0.78 ERA, the lowest recorded by a reliever since 1990. As great as that campaign was, it was followed by an extremely difficult 2019.

Treinen’s struggles ultimately led to him having to relinquish closer duties to Liam Hendriks last June. The 31-year-old’s season was cut short due to a stress reaction in his back, and he finished with a 4.91 ERA and career-high 37 walks over 58 2/3 innings. With MLB Trade Rumors projecting a salary increase through arbitration to around $7.8 million, it was going to be difficult to keep Treinen around at that number in a non-closer role, leading to the A’s looking to move him via trade before Monday’s 5 p.m. PT non-tender deadline.

Buchter’s command issues, which led to a relegation to lower-leverage situations as the year went on, contributed to the decision to not tender him a deal, but the biggest factor here may be MLB’s new incoming three-batter minimum rule for relievers being implemented in 2020. The left-handed Buchter carved out a role as a lefty specialist, holding left-handed hitters to a .238 average last season. However, of his 64 appearances, 23 of them saw him face fewer than three batters in an outing. MLB Trade Rumors projected the 32-year-old reliever to make $1.8 million through arbitration. Buchter’s spot could be filled by fellow lefty T.J. McFarland, whom the A’s signed to a one-year deal on Monday to avoid arbitration after claiming him off waivers from the Diamondbacks last month.

Phegley, who was projected to make $2.2 million, put together a career year with 12 home runs and 62 RBIs over 106 games. However, his fate with the A’s was pretty much sealed earlier in a trade on Monday when the A’s acquired catcher Austin Allen from the Padres and a player to be named later in exchange for Jurickson Profar.

Hendriks, right-hander Chris Bassitt, left-hander Sean Manaea, outfielders Mark Canha and Robbie Grossman and infielders Chad Pinder and Marcus Semien remain arbitration eligible after they were tendered contracts on Monday, leaving the A’s 40-man roster at 37 players. The arbitration-eligible players can negotiate contracts with Oakland over the next month, and if no deal is reached by Jan. 10, the two sides will swap salaries and go to an arbitration panel that either picks the player’s or the team’s offer in a binding settlement for the 2020 season.

Semien is projected to make around $13.5 million, per MLB Trade Rumors. Hendriks’ number is $5.5 million, Canha at $4.9 million, Grossman at $3.3 million, Manaea at $3.5 million, Bassitt at $2.8 million and Pinder at $1.8 million.