Twala is believed to have picked up the knock in training, and has been spotted wearing a cast during his side's last two matches.
The former Orlando Pirates attacking midfielder has only played five games for Maritzburg since his January loan signing from Kaizer Chiefs, featuring mainly as an impact player.
"Yes, Twala will be out for the rest of the season," Davids confirmed after United's 1-1 draw with Cape Town City at Harry Gwala Stadium on Saturday.
Kenyan defender Brian Onyango could also miss the rest of the campaign, having recently had knee surgery.
Meanwhile, Davids is thrilled with the exploits of striker Andrea Fileccia, who scored his fifth league goal of the season against City and eighth in all competitions.
The Belgian is making the most of his greater game-time following Evans Rusike's sale to SuperSport United in January.
"He was really working hard for the whole season, waiting for his chance, playing there and there," said Davids.
"And of course when Evans left there was a possibility to take the mandate and he's done it. He's done it and he's scoring goals."
The third-placed Team of Choice trail log leaders Mamelodi Sundowns by 10 points with five games left, and next visit mid-table Baroka at Peter Mokaba Stadium this Sunday (15h00).