Former No.2 draft pick Christian Petracca has broken his toe while playing basketball during his Christmas break.

It is yet another setback for Petracca , who is yet to play a senior AFL game since being selected in the 2014 National Draft after suffering an ACL injury last pre-season.

Petracca suffered a small crack to the little toe on his right foot.

He is expected to miss a month of pre-season training.

"Christian’s rehab up until this point has been going really well, but when you’re an AFL player, you need to understand that everything you do impacts your ability to prepare and contribute to the team and this incident is clearly an interruption," Coach Paul Roos said.

"We have been very clear as a club about not putting expectations on our first year players, so it's important to keep some perspective about this.

"It’s a harsh lesson for Christian, but one we are sure he is going to learn from as he develops as an AFL player."