Jim Harbaugh is worried that Colin Kaepernick might get too muscle-bound

San Francisco 49ers head coach Jim Harbaugh is one of the most maniacally well-prepared people in the NFL, and he's been that way for a long time. It's one of the things that allowed him to play quarterback in the pros for 14 seasons and it's what has made him one of the NFL's best head coaches.

But it seems that even Harbaugh, the man responsible for the 49ers' recent turnaround and the man Mike Ditka once called "the most competitive player I ever coached," is concerned about the level of offseason preparation his current quarterback is putting in. Not that Harbaugh thinks Colin Kaepernick isn't doing enough -- quite the opposite.

[Also:Orioles win scheduling conflict battle with NFL]

Harbaugh has warned Kaepernick about becoming too yoked-up in his intense workouts, according to a story by Matt Maiocco of CSN Bay Area.

From the recent owners meetings:

"If you're just talking about weightlifting and upper-body strength, yes, I think there is that fear," Harbaugh said. "It's something we've talked about. 'I don't want you getting too jacked-up, Colin.' I want some speed, quickness, not just [flexing his chest muscles]."

Well, we're not sure how "steroidal" Kaepernick could ever look -- he's a lean-muscle guy to be sure. Certainly, it's good that Kaepernick is working his butt off, because he'll go into the 2013 season, his third in the NFL, as the team's starter on opening day for the first time. Of course, Kaepernick's receivers would prefer that his arm doesn't get any stronger.

"When we are doing individuals with the quarterback and the receiver, guys go to the back of the line when it's Kaepernick's time," Michael Crabtree recently told Maiocco. "They try to time it out so that if Kaepernick is [throwing] third, they want to go fourth. It's a lot of heat coming."

[Also: NFL evaluators have guidelines for prospect questioning]

Kaepernick is a one-time pitching prospect who has been known to bring 95-mph heat, so that's been going on for a while. As far as the muscular concerns, it may be related to Kaepernick's recent alliance with the MusclePharm company, a partnership that was announced in Twitter by one Michael Vick.

MusclePharm is a Denver-based supplement company, and Kaepernick has been working with it for a while.

"I added MusclePharm supplements to my routine at the beginning of my rookie season in the NFL. MP covers all my needs when it comes to energy, recovery and increased productivity both on and off the field," Kaepernick said in a statement. "I am honored to become part of the MusclePharm team and look forward to representing their highly regarded brand."

MusclePharm CEO Brad Pyatt was certainly happy to have the young quarteback on board.

[Also: Former teammate calls Vince Wilfork's wife ugly]

"Kaepernick's reputation as a workout fanatic coupled with his amazing physique makes him an ideal fit with the MusclePharm brand," Pyatt said. "He is both an articulate and charismatic young man with a work ethic and competitive drive that complement his dynamic athleticism. We are thrilled to have him represent MusclePharm."

Just don't get too big, kid. You don't want to have to answer to that Harbaugh guy...

College basketball video from Yahoo! Sports:

Other popular content on Yahoo! Sports:
Best of the NCAA tournament: Day 2
Creighton player's medical condition has him fearing sudden death
Photo gallery: Best and worst NCAA cheerleader uniforms
Watch: Heat rally for 25th straight win

What to read next