But his surgically repaired hip has improved enough to let him through individual drills for the first time Wednesday morning at a voluntary workout that was open to the media.
"I feel good, a little bit ahead of schedule," Marshall said.
Marshall put on his helmet and took turns in the receiving line, running routes and catching passes for about 10 minutes.
He watched from the sidelines once the team assembled for team drills but occasionally played catch with quarterback Chad Henne when the backups were on the field.
"It feels good and it makes you feel part of the team," Marshall said.
"When you're on the sideline just watching and getting mental reps it kind of sucks a little bit, but it feels good to get out there and run around."
The Dolphins announced last month Marshall's healing hip wouldn't make him available to practice until training camp, which begins July 31.
The chief concern about Marshall's inability to work out fully is that it delays him developing chemistry with Henne, a third-year pro who's going through his first offseason as a starter.
"Any time he can come out here and have a presence," Henne said, "it's good for our team."
Marshall was the Dolphins' blockbuster acquisition. They sent a pair of second-round draft choices to the Denver Broncos and then signed him to a four-year, $47.5 million extension. He has more than 100 receptions in each of the past three seasons.
"I'm the type of guy I want to be out there, especially being in a new environment and being around a bunch of guys that aren't familiar with me," Marshall said. "So it's important to me to get out there and just do something to show them that I'm here and what I'm capable of doing."
Tim Graham covers the AFC East for ESPN.com.