WEST PALM BEACH, Fla. -- The Nationals have decided on a closer, according to manager Dusty Baker, but they are not ready to reveal who it is just yet.

"We've kind of settled on a guy, but we've got to tell the guy first," Baker said prior to Saturday's game against the Astros.

Baker did not provide a timeline of when they planned to tell the player or make an announcement, and he did not offer any strong hints on who it could be. But the decision appears to be between three main candidates: Shawn Kelley , Blake Treinen and Koda Glover .

Glover has emerged recently as a popular pick, despite his inexperience in the Majors. He has been impressive this spring, with a team-high 12 strikeouts in 9 2/3 innings while the Nats have continued to use him in the ninth inning. That normally means very little during Spring Training, but it is also no coincidence, and could be meaningful considering last year's closer, Jonathan Papelbon , was also used to close out the ninth inning in the spring.

Glover, who turns 24 in April and is the team's No. 7 prospect as rated by MLBPipeline.com, rocketed through the Nationals' system last season from Class A Advanced and ended up in the Majors by July. He started strong in his first 12 games through Sept. 6, with a 2.63 ERA and 13 strikeouts in 13 2/3 innings while holding opponents to a .447 OPS. However, his last seven games were rough, and he allowed seven runs in six innings with just three strikeouts. It was revealed during the offseason that he was pitching with a torn labrum in his hip, although it is unclear how much that impacted his performance.

Kelley, 32, was one of the top relievers in baseball last year with a 2.64 ERA, a 0.90 WHIP and 12.4 strikeouts per nine innings in a career-high 58 frames. He has also been solid this spring with a 1.42 ERA, even though he has only appeared in six Grapefruit League games and received most of his work in Minor League games. The Nats have had concerns about his durability, however, after two Tommy John surgeries in his career, and do not want to overexert his arm.

Treinen, 28, is also turning in a strong spring, and has not allowed a run in five outings, after the best season of his career. In 2016, he posted a 2.28 ERA and a 65.9 percent ground-ball rate last season, the second best in the Majors. The Nationals do enjoy having flexibility with Treinen to get them out of situations with inherited runners because of his ability to induce double plays.

On Saturday, Treinen pitched two-thirds of an inning to get the save against the Astros.

"We came into the situation with candidates," Baker said. "Whoever we pick, we have to give him a chance to succeed or fail a number of times, or else you're out there pitching with uncertainty and fear that you're going to lose whatever job you have.

"On the other hand, you can't let them fail too much, because then you're hurting us and possibly hurting him and his confidence."