A scare has forced Essendon recruit Jake Stringer from the field during an intra-club match at Tullamarine on Friday.
The former Bulldog, who joined the Bombers in October last year, hurt his foot when a teammate stepped on him during the practice game.
Stringer left the session early but the club insisted he was okay.
"Yeah, he got stomped on," the Dons' new AFLX coach Hayden Skipworth told reporters.
"We just took a precautionary approach and sent him inside.
Stringer has been working hard on his aerobic capacity since arriving at Tullamarine with the Bombers keen for him to spend more time in the midfield.
Skipworth said the 23-year-old had made huge improvements with his running but still had some work to do before round one.
"We've gone a slow build with [Stringer]," he said.
"Pre-Christmas it was all about building his tank away from the group and post-Christmas it's just been in training and a top up after training.
"He's just got to get his tank right so he can spend 70 per cent in the midfield and 30 per cent up forward. From what we've seen around the ball he's been super. We've lost a few big-bodied midfielders so he's filled that role around the contest."
The intra-club was at times a heated affair with several players being closely tagged.
Recruit Devon Smith and midfielder Darcy Parish were involved in a bit of a push and shove, showing just how competitive the Bombers are.
Midfielder David Zaharakis said it was all in good spirits.
"The competitive juices flowing is exactly what you want," he said.
"You'd rather have little biffs here when teammates are getting angry at each other but it's competitive and it's going to help us get better which is what we want.
"The boys were having a laugh about it in the change rooms. Once you walk off the track it's forgotten about because we're all teammates, we're trying to get each other better and that's what good clubs do."
Swingman Cale Hooker cut an impressive figure on the field, while Parish and skipper Dyson Heppell were very busy around the ball.
A select group of players including Zaharakis, Zach Merrett and Anthony McDonald-Tipungwuti, also took part in some AFLX match simulation.
Skipworth will take over the reins from John Worsfold in the coach's box during this month's inaugural AFLX tournament.
Zaharakis was unveiled on Friday as the Bombers' AFLX captain.
The Dons will take to Etihad Stadium on February 16, playing two round-robin matches against Hawthorn and St Kilda.
Clubs will rotate through 14-player squads with seven players on the field at any one time, and three on the interchange bench.
Teams are allowed to make up to four changes to their line-up between games.
AFLX is a fast-paced hybrid game consisting of two 10-minute halves played on a rectangular field.
Tournaments will be held at Hindmarsh Stadium in Adelaide on February 15, Etihad Stadium in Melbourne on February 16 and Allianz Stadium in Sydney on February 17.
Each club will play two pool games, with the winner of each pool to qualify for a Grand Final.