STAR Adelaide forward Eddie Betts will miss the next two weeks with a hamstring injury, ruling him out of Friday night's clash with Sydney at the SCG.

Small forward Lachlan Murphy (hamstring) and midfielder David Mackay (concussion) need to pass fitness tests this week, while former North Melbourne ironman Sam Gibson has had complications with his hamstring injury and is at least another three weeks away from debuting with his new club.

Betts sat out the last quarter of the Crows' 48-point loss to Collingwood at Adelaide Oval last Friday night with a tight hamstring.

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The 31-year-old has led the Crows' goal-kicking four times and has made the All Australian team the past three years, but has had a slow start to this season, kicking only three goals in the opening four rounds.

"Unfortunately, Eddie came off with a little bit of hamstring tightness. We expect him to miss maybe two weeks," Crows general manager of high performance Matt Hass told

"He's commenced running already and has progressed really well."

After playing the first three games of the season, Murphy injured his hamstring at a training session last Thursday.

"He had a little bit of hammy tightness, so we took a cautious approach being a first-year player," Hass said.

The Crows will also take no risks with Mackay after his second concussion in three weeks.

He copped a heavy hit and was forced to leave the ground against the Magpies, a fortnight after he was concussed in Adelaide’s round two win against Richmond.

In better news, Crows' club champion Matt Crouch could return from his hamstring injury for the round six clash with Gold Coast.

"He's taken a little while to get going, but he's progressing nicely and we expect him back in the next week or so," Hass said.

However, experienced midfielder Gibson has been delayed in making his Crows' debut due to back-related hamstring symptoms.

Gibson – who played 130 consecutive games with the Kangaroos before being traded to the Crows at the end of last year - was set to debut for his new club in round one, but injured his hamstring at the club's captain's run in Melbourne the day before the clash with Essendon.