Richmond coach Danny Frawley said Hall, who jarred a knee in yesterday's thrashing to Port Adelaide, was only a 50-50 chance to play Geelong on Saturday at the MCG, while Ottens only had a slim chance of returning from a calf injury.
The Tigers, languishing in 13th place, also have worries with ruckman Greg Stafford, who will front the tribunal tonight, charged with striking Port's Adam Kingsley.
The Tigers have had a dreaded run with injury this season, particularly in the big man department, with Ottens, Stafford, Ben Holland and spearhead Matthew Richardson all spending periods in the stands.
But in one of few positives from yesterday's 84-point loss to the Power, Frawley said Richardson had pulled up well in his first game back after missing five matches through a hamstring injury.
Adelaide expects prolific midfielder Simon Goodwin (sprained ankle) to miss just the one week after being carried off on a stretcher late in Saturday's loss to Melbourne.
Crows Kane Johnson (appendix) and Rhett Biglands (corked buttock) will be tested, but leading goalscorer Scott Welsh (groin) will miss another week.
Sydney veteran Stuart Maxfield will undergo a knee operation tomorrow and has been ruled out for the remainder of the season, while captain Paul Kelly (hamstring) will be tested.
Hawthorn defender Luke McCabe had shoulder surgery last Friday and will be sidelined for at least six weeks.
But Hawks Nick Holland (hamstring) and Angelo Lekkas (foot) face tests before Sunday's game against St Kilda.
Saints Austinn Jones (hamstring) and Fraser Gehrig (adductor) could return after lengthy stints on the sidelines.
Collingwood has its problems in attack, with forwards Chris Tarrant (hip), Anthony Rocca (hamstring) and Nick Davis (ankle) all facing fitness tests before Saturday night's game against the Kangaroos.
Fellow forwards Brodie Holland (hamstring) and Jarrod Molloy (foot) will definitely miss the game.
Essendon captain James Hird (facial fractures) trained today in a helmet and is still on track to return in round 14 against the Western Bulldogs.