Brendan Donovan out for rest of the season.

Seattle Mariners third baseman Brendan Donovan has been out for a month with a concussion he suffered after taking a baseball off the head in the team's batting cages at T-Mobile Park.

Per an update Tuesday from Seattle general manager Justin Hollander, Donovan will see a specialist Wednesday and is hoping to resume baseball activities by the end of the week, but won't play again this season.