Sorenson hurt his left hand in last week's North Harbour game and has sat out training so far this week, including yesterday's session at Blue Chip Stadium.
Warren Smith will provide cover at lock for the match, with Solomon King starting at No 8 in Smith's place if Sorenson is ruled out.
Hooker Aleki Lutui is still unavailable, though he did run freely at training, while Colin Bourke was on light duties.
The pair are likely to be considered for the Manawatu match next week and target a starting berth against Tasman the week after, while midfielder Jeff Ierome is in a similar position.
The other injury concern was with reserve halfback Garrick Cowley, who also sat out training with a sore shoulder. Mount Maunganui's Sam Moon was called in as cover. Moon's Mount team-mate Lance MacDonald has recovered from an ankle problem suffered five weeks ago in club rugby and trained on the right wing for the Steamers.
He's likely to be given a run on Sunday as Steamers coach Andre Bell seeks solutions to a rusty backline that is struggling to unleash its potential.
Bell hasn't been helped by three tough matches to start the Air New Zealand Cup season and the match in Auckland won't get any easier.
He's facing a tough decision on whether to persevere with first-five Murray Williams, who appears to be low on confidence, or to give Mike Delany a run there. Delany has started against Wellington and North Harbour at fullback but MacDonald, Hayden Reid and Charles Baxter can all play there.
Rookie midfielder Wayne Hughson impressed in his first start against North Harbour before he cramped and had to go off in the second half.

With thanks to the Bay of Plenty Times