No rest for the weary or the reputation-repairers.

Ninersnation.com is reporting that San Francisco 49ers quarterback Colin Kaepernick has returned to Phoenix to continue working at EXOS Performance.

San Francisco 49ers QBs coach warns more running will mean less effective passing for Colin Kaepernick

The Niners quarterback, entering his fifth year in the league, has spent the entire offseason working on becoming a more efficient pocket passer. He earned rave reviews from teammates and onlookers during the team's offseason activities but isn't resting on his laurels.

Kaepernick turned in the worst quarterback rating of his three years as a starter in 2014 and went to the EXOS Training facility to improve on his passing aspects as a quarterback.

Colin Kaepernick's mechanics work includes placement of non-throwing arm

Among the changes Kaepernick has made has been to make his throwing motion more compact for a quicker release. He widened his base, allowing him to take a shorter step into the throw. Kaepernick also is generating more power from his legs, which means he don't have to wind up and unleash the ball like he had been doing last season.

He also is keeping his non-throwing arm closer to his body when he throws, which has increased his accuracy downfield.

The 49ers quarterback also is throwing shorter routes and screen passes to his running backs with more touch on the football.

The new 49ers offensive staff, including new offensive coordinator Geep Chryst and quarterbacks coach Steve Logan, say they still want to utilize Kaepernick's running ability, but he has to learn when to pull down the ball, tuck it and run, and when to stay in the pocket to give his receivers the chance to get open and make plays.

The only concern for Kaepernick, in the second year of a seven-year, $126 million deal, is whether he'll experience any burnout at the end of the season for having spent so much of his offseason working on his game.