Entwistle was waived by the Panthers on Tuesday, according to Elliotte Friedman of Sportsnet.
Entwistle signed a one-year, two-way contract with Florida on Tuesday.
Entwistle is not expected to receive a qualifying offer from the Blackhawks on Sunday, per Ben Pope of the Chicago Sun-Times.
Entwistle posted an assist and three hits in Thursday's 5-4 overtime loss to the Kings.
Entwistle notched an assist in a 5-2 loss to St. Louis on Wednesday.
Entwistle scored a goal in a 3-2 overtime loss to the Red Wings on Sunday.
Entwistle (illness) will be in action versus the Avalanche on Tuesday, Mark Lazerus of The Athletic reports.
Entwistle (illness) is not expected to play Sunday against Vancouver, Tracey Myers of NHL.com reports.
Entwistle will be a game-time decision against Seattle on Thursday due to illness, Ben Pope of the Chicago Sun-Times reports.
Entwistle (wrist) was placed on injured reserve Tuesday.