"Nothing's official," Packers head coach Matt LaFleur said Wednesday. "Until then, I'm not going to say much about it."
When asked whether the signing will become official soon, LaFleur responded: "We shall see."
Mercilus, who was released by the Texans on Tuesday after spending 10 seasons with the franchise, turned down more lucrative offers to join the Packers, according to reports. The Kansas City Chiefs were among the teams in the mix for the outside linebacker.
In six games for the Texans this season, Mercilus -- a first-round draft pick in 2012 -- notched 12 total tackles, three sacks and three quarterback hits. His 57 career sacks for Houston rank second in franchise history behind J.J. Watt, who registered 101 sacks with the Texans.
The Packers were already playing without Pro Bowl edge rusher Za'Darius Smith, who played just 18 snaps in the team's season opener before undergoing back surgery that has him out indefinitely. Green Bay then lost outside linebacker Preston Smith to an oblique injury during Sunday's game against the Chicago Bears.
Packers outside linebacker Chauncey Rivers, meanwhile, suffered a season-ending knee injury earlier this month, leaving the team thin at the position.