West Coast defender Jeremy McGovern has had his day cut short after suffering a groin injury against Geelong.

McGovern was subbed out of the match after being aided off the field and placed under further assessment by club medical staff.

The star defender was ruled out of the match in the second quarter, with medical sub Brayden Ainsworth brought into the game.

Meanwhile, Sydney midfielder George Hewett has been subbed out of his side's clash against the Suns after a nasty collision.

Hewett and Suns swingman Chris Burgess collided during a contest in the opening quarter, with Hewett taken off the field for assessment.

The 25-year-old was soon ruled out of the match, with rookie defender Braeden Campbell subbed into the match.

Swans forward duo Tom Papley (ankle) and Nick Blakey (quad) also suffered niggles in the opening term, with the Suns winning the first quarter 26-19.