Collingwood defender Sam Murray is allegedly under investigation after a post-match drugs test last month.

The Australian Sports Anti-Doping Authority last week made the 20-year-old aware of an elevated reading for an illicit substance stemming from the test, AFL.com.au reports.

The 13-game player, who crossed to the Magpies from Sydney at the end of last season, was picked for last Saturday’s clash against Port Adelaide but was later withdrawn for what the club said was “personal reasons”.