When a club "non-tenders" a player, it declines to give that player a contract for the upcoming season, thereby immediately making him a free agent. Players on the 40-man roster with fewer than six years of Major League service time must be tendered contracts each offseason by a set deadline -- typically a date in early December -- or non-tendered and released to the free-agent pool.
In many instances, a club will non-tender a player because it feels the raise he will receive in arbitration would be greater than his on-field value. In other cases, a club will non-tender a player simply to clear a spot on the 40-man roster -- even if that player isn't due much more than the league minimum the following season.
Henderson Alvarez was due to receive $4 million or more in arbitration following the 2015 campaign, in which he made just four starts before undergoing season-ending shoulder surgery. Rather than tender a contract to a player with major durability concerns, the Marlins non-tendered Alvarez in December 2015.
Also in December 2015, the Astros elected to non-tender first baseman Chris Carter rather than pay him a raise on his $4.175 million salary from the prior season.
And though James Jones was not eligible for salary arbitration and would have made scarcely more than the league minimum in 2016, the Rangers non-tendered him in December 2015 to open a 40-man roster spot for further offseason maneuvering. Texas soon re-signed Jones to a Minor League contract, keeping him in the organization without expending a 40-man roster spot.