The Nationals selected Barnes to the major-league roster Sunday.
The veteran right-hander signed as a non-roster invitee early in camp and pitched well in Grapefruit League action with three strikeouts and no walks over 3.2 scoreless frames. Barnes struggled to a 5.48 ERA in 24 outings for Miami last season and should begin 2024 in a middle-relief role, though his experience as a closer makes him a logical option for higher-leverage spots with a strong start to the campaign.