Adelaide wingman Brodie Smith will be sidelined for eight weeks after breaking his collarbone.
The 21-year-old was injured in the Crows' 16-point victory over hometown rivals Port Adelaide in the NAB Cup.
Smith had been one of the Crows' best players in the 26-point loss to St Kilda earlier in the day.
But his luck ran out when he landed heavily after attempting a tackle early in the first half of the Power clash.
Coach Brenton Sanderson admitted Smith would be tough to replace.
"It's disappointing, Brodie is such an important player for us and had a fantastic year in 2012," said Sanderson.
"It'll test our depth, but we saw on Sunday we've got some players who can stand up.
"Knowing Brodie, he'll be very diligent in his rehab and will work his way back into the side early in the season."
Smith, who was taken with the 14th overall pick in the 2010 Draft, has played 36 games over two seasons.
Sanderson was far happier with Adelaide's display against Port, where Josh Jenkins kicked two goals.
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The reigning NAB Cup champions had disappointed against the Saints, though Graham Johncock kicked three goals.
Sanderson expects former Tiger Richard Tambling to seriously challenge for a spot in defence, in the absence of Smith.
Tambling was named the 2012 best and fairest for Sturt in the SANFL, and was listed as an emergency for five of the last rounds of the AFL.
The 26-year-old played 108 games for Richmond over six seasons before joining Adelaide ahead of the 2011 season.
Adelaide are 11.00 to win the AFL Premiership.
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