Carlton are facing the prospect of losing Zac Williams for the AFL season opener against reigning premiers Richmond after the boom recruit's high bump on Hunter Clark.
Williams jumped off the ground and made high contact with his St Kilda opponent in the opening stages of the Blues 26-point defeat in a pre-season series match on Thursday night.
Clark got up quickly but stumbled briefly before carrying on.
The incident is certain to be scrutinised by the match review officer as Carlton prepare to take on the Tigers at the MCG on March 18.
"Everyone's talking about it, so there must be something to worry about," Blues coach David Teague said.
"I briefly looked at it on the phone and to be honest the view wasn't great, so I'm not exactly sure.
"I've loved having him at our footy club and really hope he's available (for round one)."
Williams and fellow recruit Adam Saad were among the Blues' best against St Kilda in a largely free-flowing game, showcasing the speed and skill that made them both attractive off-season targets.
Williams finished with 17 disposals, seven inside 50s and two goals from four shots.
"When we needed someone to stand up around the contest and be tough I thought his ability to win the ball and use it and get the ball going our way was very good," Teague said.
"He plays a role in the forward half, as well, and I think he kicked a couple (of goals) from forward-50 stoppages, which was exciting."
Carlton defender Jacob Weitering had trouble with a corked hip and Jack Newnes suffered an ankle injury, while key forward Harry McKay hurt his troublesome ankle again.
"I don't know if (McKay) tweaked it or he felt it was sore, but we said all along that if any of our boys get too sore (we'd take them off)," Teague said.
"They've had a great training block leading into it and we've pushed them pretty hard to this stage, so we've got a lot of confidence that they'll be able to run out the season."
