Zimmer, 61, returned to the field for the third OTA session, which runs Monday through Thursday.
Zimmer has battled eye problems since scratching the eye during the loss at Chicago on Monday Night Football on Halloween.
Zimmer has undergone eight different surgeries on his eye, per Tomasson.
When asked on Tuesday if the leave was worth it, the prideful Zimmer let out a sigh and paused for several seconds.
In the open portion of Tuesday's Organized Team Activities at Winter Park, the Minnesota Vikings left quarterback Sam Bradford on the sideline, allowing Case Keenum and Taylor Heinicke to split snaps with the first team.
Doctors discovered Zimmer had a torn retina last November. He missed a December 1 game against Dallas because of emergency surgery the previous night for a detached retina.
"It is hard to tell if it is 20/20 or 20/800 because you cannot really tell any of that, but I can see decent", Zimmer said. He had his first surgery the following day. The real stakes are Zimmer's health, not his ability to recalibrate the Vikings into Super Bowl contenders after their humbling 2016 collapse.
"So we know he's watching and that's obviously why we work so hard".
"I'll be back shortly with one eye or two", Zimmer said in a May 26 conference call with the media.
Zimmer said he is "probably the most optimistic" he's been that this will be the final procedure.
"The doctors all got together and we had a long meeting about what's the best for my recuperation of this eye and they are saying I need to spend the next couple weeks working on my recovery". "I'm very lucky and very fortunate to not only have the coaches I have, but the team that I have".