So much of an N.F.L. quarterback’s job is persona, and Jackson is beloved around Ravens headquarters for more than just the amazing things he does with a football. He earned his teammates’ trust with his comportment last season, when in Week 10 he replaced Joe Flacco and, operating a scaled-back playbook, won six of eight games. That trust has grown in his second year.

“His mind-set going into the season was just like: ‘I’m going to throw this thing. I’m throwing the ball this year. I’m going to prove to everybody that I can throw the ball,’” receiver Willie Snead IV said.

Snead and running back Mark Ingram spent a week in July with Jackson in Florida, running routes and learning each other’s tendencies. Their time punctuated a methodical off-season reset for Jackson that started in February at his old youth field, McNair Park in Pompano Beach.

Since he had spent the previous two years darting from one major moment — Heisman campaign, draft prep, replacement starter — to the next, he and Harris, the personal coach, felt it was imperative to approach their work slowly, with purpose.

For three hours a day, five days a week, Jackson retrained his muscle memory, isolating the three basic elements of the passing motion — step with the front foot, turn the back hip, bring the arm through — then repeating them together in sequence.

Harris noticed that as chaos enveloped him last season, Jackson tucked the ball and ran instead of keeping his eyes downfield. If he did pass, his mechanics lapsed. Harris worked on Jackson’s footwork, ensuring that he generated velocity by rotating on the ball of his back foot.

Throughout the summer, Harris maintained contact with Baltimore’s quarterbacks coach, James Urban, texting him videos of drills and relaying details of Jackson’s progress. The collaboration liberated Jackson, who was relieved to learn, for instance, that he could maintain his peculiar grip — his index finger touches the nose of the ball, à la Kurt Warner, and not the laces — as long as his throws were on time and accurate.