Treadwell, 21, was the No. 23 overall selection in the 2016 NFL Draft. The Mississippi product had 15 yards in nine games.
"I think Laquon has a better understanding of things," Zimmer told the Minnesota Star Tribune. "I don't think he understands quite some of the subtleties that he needs. I think he's got the basics down pretty good. He had a lot of injuries. Then he was pressing. Then I think he just has to come in and be an athlete."
With Cordarrelle Patterson and Charles Johnson leaving the team in free agency, it will likely be Treadwell who is asked to step up most.
Zimmer told ESPN in March that he is expecting "growth" from the young pass catcher.
"Laquon came in, and he had some durability issues through OTAs, and had some things on and off during camp," Vikings general manager Rick Speilman told the St. Paul Pioneer Press in February. "I know that he is maybe the hardest-working kid I've ever seen. He is so determined to be a good player, and he has the skill set to do it. But we were never able to get him on track. He is going to be a good player with us. I do believe that in my heart."
Treadwell dealt with several injuries last season, coming off a junior season with the Rebels where he had 82 catches for 1,153 yards, and 11 touchdowns. He is due $901,590 this season and is signed through 2020. He heads into the 2017 season with Stefon Diggs, Adam Thielen, and Jarius Wright ahead of him on the depth chart.