The Red Sox designated veteran first baseman Eric Hosmer for assignment on Friday, in conjunction with a deal with the Royals to add right-hander Wyatt Mills. Boston sent Minor League righty Jacob Wallace to Kansas City in the trade.

The move signifies a vote of confidence in rookie Triston Casas as the potential starting first baeman next season. Casas, like Hosmer, is a left-handed hitter; Boston will likely look for a right-handed bat to complement Casas.

Hosmer was acquired from the Padres last August at the Trade Deadline in a deal for former first-round pick Jay Groome. As part of the deal, San Diego had agreed to pay the majority of the $44 million left on Hosmer's contract through 2025, leaving Boston simply to pay the league minimum. In 14 games for the Red Sox, Hosmer hit .244 with four RBIs.

In 12 years in the Majors, Hosmer has hit .277 with 196 home runs for Kansas City, San Diego and Boston.