Some habits, for Colin Kaepernick, are hard to break.

The San Jose Mercury-News posted a tweet from running back Mike Davis, the San Francisco 49ers' fourth-round draft choice out of South Carolina, discussing one of Kaepernick's passes that he delivered Wednesday as the team finished its first week of organized training activities.

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Part of Kaepernick's offseason work with two-time NFL MVP Kurt Warner and quarterbacks coach Dennis Gile was to vary the velocity in his passes, develop touch in passes in which the fastball was either not required or actually a detriment.

Warner lauded Kaepernick's improvement, but Davis apparently didn't get Kaepernick's changeup.

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"Kap, man, I didn't know he could throw the ball that fast," Davis said, according to the Mercury News. "I still caught it. ... It's sore a little bit, but I'm fine now."

The newspaper reported that Davis did drop a sideline pass that Kaepernick threw into a tight window Thursday but didn't show any ill effects of the thumb injury.

Davis, the Mercury News reported, is just the latest in a line of players to feel the wrath of the Kaepernick fastball.

Randy Moss dislocated a finger trying to catch one of Kaepernick's passes during his starting debut in 2012 - although Kaepernick may have had a little more adrenaline for his first career start.

Last year, wideouts Stevie Johnson and Bruce Ellington talked about their experience with Kaepernick's throws.

"I had my fingers in the ice tub just a few minutes ago, so I'm trying to get ready for next week already," Johnson said last May.

"Kaepernick has got a cannon," Ellington added. "It's a lot different from catching them college balls. It's coming. As soon as you get out of your break, the ball's right there."

The stories make for amusing anecdotes - as long as Kaepernick remembers to change speeds where applicable next season. The 49ers could be in for a long season, if Kaepernick reverts to his fastball-only form.

Do you think Colin Kaepernick will remember his offseason training during crunch times next season? Comment below or tell us @SportsWN.