San Diego just promoted Watts to their active roster ahead of their Monday night game against the Bears, so it would not be surprising to see him return to their practice squad in the coming days.
McGrath, 27, originally signed on with the Seahawks as an undrafted free agent out of Henderson State back in 2012. He spent a over a year in Seattle before later being claimed off of waivers by the Chiefs.
Last year, McGrath made the decision to retire from the NFL. However, this decision was short lived as he changed his mind a few months later after being cut by Kansas City.
McGrath later caught on with the Colts, but has been on and off of their roster ever since.
McGrath last appeared in a game during the 2013 season when he registered 26 catches for 302 yards and two touchdowns for the Chiefs.