Terry Antonis will be sidelined for the next month with a knee injury Sydney FC revealed today.

The talented 17-year old sustained the injury in last Friday's National Youth League match against Adelaide United and will now be out of action for around four weeks.

"It is disappointing for me because I love playing. I have learnt a lot this season and I guess this is another part of football. I will be patient and do what the staff say and work back into it," Antonis said.

"We have some big games coming up which we need to win to make the top six so it will be weird having to watch but I know the boys can do it.

"The month will feel like a lot more but like I said, I must be patient."

Antonis has appeared five times for the Sky Blues seniors this season and is tipped for big things at the club.