KANSAS CITY -- The deadline for non-tendering a player's contract is Friday at 7 p.m. CT, and there's a good chance the Royals will non-tender only one player.
The club will have four players -- pitchers Kelvin Herrera, Brandon Maurer, Mike Morin and Nate Karns -- eligible for arbitration who could be non-tender candidates.
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Here's a look at the four:
Kelvin Herrera
The right-handed reliever made $5,325,000 in 2017, and he came into camp as the clear choice to replace Wade Davis as the closer. But after a promising start, Herrera struggled and he wound up blowing five saves and had three losses before eventually losing the closer's role in September to Mike Minor.
It's highly unlikely the Royals will non-tender Herrera, even though, according to MLB Trade Rumors, he could get up to $8.3 million via arbitration with his 26 saves and 4.25 ERA.
Club officials do not feel Herrera is comfortable in the closer's role anymore, but it is more likely they either go to arbitration with him or try to trade him as a part of the pending rebuilding process. Herrera still possesses a 96-98 mph fastball and should get interest from other clubs.
Brandon Maurer
The right-hander came over from the Padres in a non-waiver Trade Deadline deal, and there were high hopes Maurer could shore up the bullpen. But Royals officials and coaches are baffled that his stuff (95-98 mph fastball, hard slider) doesn't translate to better results. Maurer posted an 8.10 ERA with Kansas City. Perhaps new pitching coach Cal Eldred can unlock his potential.

Maurer also is highly unlikely to be a non-tender candidate. He made $1.9 million last season and is projected by MLB Trade Rumors to make $3.8 million in arbitration. The Royals are convinced he can be a closer candidate.
Mike Morin
The right-hander was a late-season claim off waivers from the Angels, and he didn't show much -- a 7.94 ERA in six games. He's a possible non-tender candidate, perhaps to just open a spot on the 40-man roster as he wouldn't be a salary saver -- Morin made $535,000 last year and is projected to make $700,000 in arbitration.

Nate Karns
Karns, a right-hander, is coming off thoracic outlet syndrome surgery, but he should be ready by Spring Training. As of now, the Royals are hoping he will be a staple in the rotation. Karns was terrific in May before he broke down and required surgery -- 3-1 with a 2.01 ERA and 32 strikeouts in 22 1/3 innings. Karns made $571,000 in 2017 and is projected to make $1.4 million in arbitration. The Royals are willing to invest that for a guy they think can be a No. 3 starter if healthy.