The midfielder sustained an ankle injury during Saturday's 2-0 defeat at Bolton and an MRI scan has confirmed ligament damage, meaning he is expected to play no part in Wanderers' final five fixtures as they strive to avoid relegation.
Davis joins goalkeeper Carl Ikeme (broken hand), leading scorer Sylvan Ebanks-Blake (broken leg), playmaker Bakary Sako (hamstring) and midfielders Dave Edwards (metatarsal) and Razak Boukari (calf) on the sidelines.
Boss Dean Saunders told the club's official website: "It's another freak impact injury I suppose. We got the MRI scan on Monday and I think he's out for the rest of the season with ankle ligament damage.
"The impact injuries are surprising - I broke my nose, but I never broke any bones in my feet or my legs.
"And to lose possibly six players in four weeks - three to broken bones with Carl Ikeme, Dave Edwards and Sylvan Ebanks-Blake - is a nightmare.
"These are mostly all players who have been regulars."
Meanwhile, full-back Matt Doherty is also a doubt for Saturday's crunch clash at home to fellow strugglers Huddersfield having rolled his ankle at the Reebok Stadium.