Davis dislocated his right shoulder in an attempt to tackle Saints skipper Nick Riewoldt early in the second quarter at AAMI Stadium on Saturday night.
It was the 20-year-old's first game back after spraining the same shoulder in the Crows' loss to Fremantle in round three.
He will have surgery later this week, but the club is unable put a timeframe on his return until surgeons uncover the extent of the damage.
Davis is the third Adelaide player alongside Jason Porplyzia and David Mackay to have shoulder surgery this season.
The Crows defence will be stretched against Melbourne at the MCG on Sunday, with utility Scott Stevens (illness) and defender/midfielder Andy Otten (knee) already ruled out of the clash.
Otten will miss between 1-3 weeks after reporting soreness in the knee he had reconstructed in late 2009.
The club is continuing to take a cautious approach with Stevens, who has been troubled by the after-effects of a head knock suffered at training last month.
He has been excluded from training again this week.
Budding defender Daniel Talia (Achilles) is also unavailable for selection.
Midfielder Rory Sloane is likely to return to give the midfield a boost after five weeks on the sidelines with a fractured thumb and jaw, and assistant coach Matthew Clarke said the club had several other options at the selection table.
"In terms of talls, James Sellar and Ivan Maric both played pretty good footy on the weekend and Chris Schmidt has been in really outstanding form for West Adelaide," Clarke said.
"Myke Cook went back and had to play reserves on the weekend because South Adelaide had the bye, but he fought pretty strongly.
"Bernie Vince [and Jared Petrenko] played well for the Eagles as well, so there are some players back there that are knocking on the door."
Rebounding defender Richard Tambling will also miss the trip to Melbourne after accepting a one-match ban for striking St Kilda forward Adam Schneider.
Katrina Gill covers Adelaide news for afl.com.au. Follow her on Twitter: @AFL_KatrinaGill
