Lawrence, 30, was banned for delivering a hit to the head of Saskatchewan Roughriders quarterback Zach Collaros on the first drive of the season.
The appeal means the veteran linebacker will likely play in Hamilton's Week 2 matchup against the Toronto Argonauts as the issue isn't expected to reach arbitration until next week, adds Lalji.
The CFL issued a statement following the appeal, saying it was "deeply disappointed that the CFLPA has decided to contest the league's attempt to punish and deter a dangerous play."
Collaros was unable to return to the Week 1 contest and was later placed on the six-game injured list. Lawrence apologized to the quarterback in a postgame interview, saying the hit wasn't intentional.