Bulldogs forward Eastwood out for a month

Canterbury's Greg Eastwood will undergo ankle surgery that is set to rule him out for the next four NRL rounds.

Canterbury forward Greg Eastwood has been ruled out for a month following ankle surgery. (AAP)

Canterbury forward Greg Eastwood has been ruled out for a month after the NRL club confirmed he will undergo ankle surgery.

The in-form New Zealand international was injured in Sunday's controversial 32-20 NRL loss to Canberra at GIO Stadium.

Eastwood is off-contract at the end of the year and is reportedly set to sign a big-money two-year extension to stay at Belmore.

The 29-year-old is reportedly being chased by several rival clubs after a strong start to the season, while it's believed the Bulldogs have offered him a $1 million two-year extension.