WESTERN Bulldogs midfielder Daniel Cross will undergo exploratory surgery on his ankle on Monday night, after injuring it in Saturday's game against West Coast.

The injury could mean Cross could miss the start of his side's finals campaign although the Bulldogs were unsure exactly how long Cross was expected to be out for.

The Bulldogs face a tough run to the finals that will be even harder without one of their biggest ball-winners and strongest tacklers. The Dogs take on the Brisbane Lions at the Gabba, Geelong and Collingwood in the final three round of the season.

Cross is the leading tackler at the Bulldogs with 84 tackles for the season and the second-best ball-winner behind Matthew Boyd.