That's why it was a pleasant surprise to see Marshall in his Dolphins helmet and running routes during drills at Wednesday morning's voluntary workout.
"I feel good, a little bit ahead of schedule," Marshall said.
Marshall, recovering from hip surgery the Dolphins didn't know he needed when they sent two second-round draft choices to the Denver Broncos for him, caught passes for about 10 minutes.
He took off his helmet and watched from the sideline once team drills began. He 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."
Marshall expressed confidence in making up for the lost time once training camp begins in late July. The Dolphins already staged their mandatory minicamp and have just two more voluntary workouts remaining.
"It's important to get that chemistry going, but we have a bunch of practices starting in August and we'll be fine," Marshall said. "We'll get a rhythm, and we'll get a chance to get on the same page, not just with me but with the whole offense."
Another bit of Marshall news for you jersey aficionados: His number choice is official.
He will stick with No. 19, of which he had considered switching out. He wore No. 15 with the Broncos, but that belongs to Dolphins receiver Davone Bess, who wasn't interested in parting with it. Ted Ginn wore No. 19 for the Dolphins last year.
Marshall said 19 was "the number I liked when I came out of college in 2006, and the Broncos threw two jerseys down on the desk, No. 15 and No. 19. And my cousin told me to pick 19. I ended up picking 15, so cuz, I've got 19 now."