HAWTHORN midfielder Jonathan O'Rourke will miss up to a month after suffering a hamstring injury, Hawks coach Alastair Clarkson says.

The 22-year-old played seven games in his second season at Hawthorn last year after switching from Greater Western Sydney at the end of 2014.

Clarkson told AFL Media's Ask the Coach series that O'Rourke would miss the early rounds of the season to nurse his injured leg.

"O'Rourke came back this weekend but has hurt his hamstring and will miss another 3-4 weeks," Clarkson said on Wednesday.

O'Rourke was hampered by a hamstring injury last year that ruled him out between rounds six and eight.