Gambrell was traded to Boston on Friday as a player to be named later in the deal that sent Andrew Benintendi to the Royals, Julian McWilliams of The Boston Globe reports.
Benintendi was moved to the Royals last offseason in a three-team trade that also involved the Mets, but there remained parts of the trade that had not been completed as of Friday. Gambrell will now head to the Red Sox organization after spending 2019 and the beginning of this season in the lower levels of the Royals' farm system.