The Ireland international, who hasn't played since suffering a dislocated shoulder in the province's New Year's Day win over Munster, had been on track to return for last week's trip to Thomond Park before a setback.
And head coach Pete Wilkins has confirmed that this weekend's visit of the Stormers to Galway is also likely to come too soon for the 26-year-old.
"Mack's on a week-by-week basis really. His shoulder is recovering well but it's just getting through that final hurdle of the contact work he has to do.
"He's being assessed every week, it's very unlikely it'll be Stormers."
The 47-12 defeat to Munster last weekend leaves Connacht ninth in the URC table with two games left to play, first at home to the Stormers, before they travel to Leinster in the final round.
The province are four points back from Benetton, who occupy the final play-off spot, although a top seven finish may be required to secure Champions Cup qualification if the Sharks win the Challenge Cup.
While Hansen is set to miss out on the visit of the fifth-place Stormers, Wilkins is hoping to welcome Santiago Cordero into his side for a debut on Saturday.
The Argentina international suffered a torn anterior cruciate ligament just days after starting pre-season training with the province last summer, but the 30-year-old is on track to be involved at the Dexcom Stadium this weekend.
"We're getting a few others back. Santiago Cordero will possibly come into the frame this week.
"He's making terrific progress so we'll monitor him this week, and if we can get him back that would be excellent before the end of the season.
"Matthew Devine took a heavy blow to the ribs, left the field early against Munster, which puts him in doubt. There's a few moving parts in the backs at the moment, but we'll have full faith in the guys available when the time comes," Wilkins added.
Disclaimer: The copyright of this article belongs to the original author. Reposting this article is solely for the purpose of information dissemination and does not constitute any investment advice. If there is any infringement, please contact us immediately. We will make corrections or deletions as necessary. Thank you.
