Collingwood defender Brayden Maynard injured his quad during the Magpies' main session on Friday.
Scans confirmed there was no structural damage, but he will be on light duties for at least the next few days.
Exciting untried youngster Harry DeMattia, meanwhile suffered a head knock and is set to enter concussion protocols.
It follows the club confirming on Thursday that Darcy Moore's recovery from injury was tracking slower than expected putting him in doubt for Opening Round, while Beau McCreery, Lachie Sullivan and Dan McStay, Jeremy Howe and Isaac Quaynor are also currently away from main training.
Meanwhile, hard working tall utility Billy Frampton completed only light running during the session.
Jordan De Goey looked strong through the midfield and worked hard both ways, setting himself a strong base for 2026, having not missed a pre-season session.
Noah Howes was a strong target inside 50 during match simulation, while Jamie Elliott caught the eye, Josh and Nick Daicos linked up on several occasions and Tyan Prindable was again the most impressive young player as he pushes for an early season debut.
