Tristan Thompson is continuing to grind through the holiday season.The 31-year-old Canada native, who last played in the NBA for the Chicago Bulls, was pictured in a workout shot he posted to Instagram Stories Tuesday, days after Khloe Kardashian, 38, publicly revealed a pic of their four-month-old son after attending her family's annual Christmas party.Thompson was seen stretching a white towel donning a necklace and black shorts and white socks as he stood in a gym that had football and basketball jerseys lining its walls. The latest: Tristan Thompson, 31, was pictured in a workout shot he posted to Instagram Stories Tuesday, days after Khloe Kardashian, 38, publicly revealed a pic of their four-month-old son after attending her family's annual Christmas partyThompson, who has past played for the Cleveland Cavaliers, Boston Celtics and Sacramento Kings, looks to be remaining in game shape in hopes of getting picked up by a team for the stretch run.Thompson and Kardashian - who are parents to daughter True, four - welcomed their son this past July 28 via a surrogate.