The Pro Bowler also missed the team's organized team activities as he attempts to land a new contract.
Donald is heading into the final year of his contract after the team picked up the fifth-year option on his rookie deal.
The defensive tackle also held out last season, missing all of training camp before returning just before Week 1 of the regular season. Per Ian Rapoport of NFL Network, the Rams waived the $1.5 million in fines he accrued during that span.
It appears there could be a similar situation this year, with Steve Wyche of NFL Network reporting Monday that negotiations were "in flux" between the Rams and Donald:
General manager Les Snead has hinted the 27-year-old will get a big contract, saying in April he is on the "verge of being the highest-paid defensive player in football," via Chris Wesseling of NFL.com. However, it appears the two sides haven't been able to come to a deal.
The negotiations have fortunately not slowed down Donald on the field.
Despite missing two games last season, he totaled 11 sacks and was named the league's Defensive Player of the Year. He has been selected first-team All-Pro in each of the last three years.
Los Angeles has to pay him like a superstar before he hits free agency.