Head coach Brad Childress, however, already knew all of that.
"What does he look like throwing the football? I am buying that throwing motion," Childress said draft weekend. "I'm not expecting to change it or move it around. It is like buying cars; if you don't like that one, you go to the next one. He has a great throwing motion. He is athletic."
Another Vikings official said Jackson should never get a sore arm with his throwing motion and noted his large hands, an asset for quarterbacks. Koren Robinson said Jackson reminds him of Michael Vick with his easy demeanor and strong arm.
Saturday, Jackson got to prove the accolades and disprove the criticism in front of his teammates and the media. Although it was Jackson's first practice in a Vikings uniform (or at least a red jersey that the quarterbacks wear), his physical skills were apparent. He looked to have the strongest arm of the four and still had some touch on his short passes.
"Tarvaris I saw made a couple of nice throws. I thought it had a little something on it, and he did a good job with all of our verbiage. I thought stepping up in the huddle and taking command of the huddle, he did a nice job there too," Childress said after the morning's two-hour session."
For his part, Jackson wasn't intimidated by the process of his first NFL practice, but there is plenty for the former Division I-AA quarterback from Alabama State to digest.
"As you learn your plays, you've got to learn who to read, the steps of the route and all of that type of stuff. There's just a lot of stuff you have to remember," he said. "It's just the minicamp playbook so far and that's pretty thick, so I'd hate to see the season playbook."
Veteran quarterback Brad Johnson could help that process.
"He is an older guy, he won a championship," Jackson said of Johnson on draft weekend. "Actually, my quarterback coach (at Alabama State, Reggie Barlow) played receiver with (Johnson) at Tampa Bay. He told me a lot about him. It'll be a great fit for me. He is a little older, but he is still playing really well. I just want to get in there and learn as much as possible from him before he leaves the game."
Although Jackson got rave reviews about Johnson, who will turn 38 years old in September, the tutelage process hasn't started yet. He just met Johnson Saturday morning for the first time, but already Jackson displayed a veteran move in practice.
On one occasion, he went to a hard count and was able to draw several offensive and defensive linemen into false starts and offside.
It was just one practice, but Jackson showed that Childress shouldn't be the only one "buying that motion" or the athletic skills. Still, it will be some time before Jackson is expected to see the field during a regular-season game. For now, however, the initial reviews were positive.