ADELAIDE midfielder David Mackay will miss up to a month with a hamstring strain.

The 27-year-old sustained the injury during the Crows' loss to the Western Bulldogs on the weekend.

General manager of high performance Brett Burton said, "David experienced hamstring soreness in the second half of Saturday night’s match and sat out the last quarter.

"Unfortunately, further assessment has revealed a hamstring strain that will keep him sidelined for 3–4 weeks."

Mackay has played all seven games this season, averaging 18 possessions and four inside 50, and marked his 150th AFL game against Fremantle in round six.

Mackay's injury means the Crows will need to make at least one change to their team to play Geelong at Adelaide Oval on Friday night, and will weaken a midfield that will come up against former favourite son Patrick Dangerfield.

The club's next four games are against the Cats, Gold Coast, Greater Western Sydney and St Kilda.