According to Gary Klein of the Los Angeles Times, Donald is highly unlikely to make an appearance unless he and the Rams are able to agree to a new contract.
Donald is set to enter the final year of his deal, and he is scheduled to earn a base salary of just under $7 million, per Spotrac.
The 26-year-old is a four-time Pro Bowler and three-time All-Pro first-team selection who is coming off a 2017 season that saw him win NFL Defensive Player of the Year honors.
Donald registered 41 tackles, 11.0 sacks and five forced fumbles en route to winning the award.
The Pittsburgh alum sat out voluntary workouts, mandatory minicamp and training camp last season before returning to the Rams at the start of the 2017 campaign.
According to Klein, Donald is believed to be seeking more than $20 million per season.
Rams general manager Les Snead recently said, "The goal is still the same. Make Aaron Donald a Ram for a long, long time."
Los Angeles has loaded up on the defensive side of the ball this offseason, adding defensive tackle Ndamukong Suh and cornerbacks Marcus Peters and Aqib Talib.
The Rams also acquired wide receiver Brandin Cooks in a trade with the New England Patriots.
Provided the Rams can satisfy Donald and prevent him from holding out into the regular season, they are poised to be one of the top contenders in the NFC.