Jerick McKinnon didn't fare well in the eyeball test, and he flunked the arm test.
When he was in high school, the 49ers' new lead runner had exactly one suitor, the University of Illinois, from a large college program. Illinois was interested in him as a defensive back and one day sent an assistant coach to his Marietta, Ga., high school expressly to measure McKinnon's arms.
They were short.
Illinois ended up giving the scholarship to another defensive back prospect from the Chicago area with longer arms. McKinnon is now in the NFL and recently signed his second contract; the kid from Chicago isn't.
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The lesson – and one that McKinnon has administered several times since – is that the experts were sizing up the wrong thing.
"He's an exceptionally hard worker," McKinnon's high school coach, Billy Shackelford, said. "And I'm not saying this because he's arrived and he's in the NFL now and all that. I told people this when he was a young, undersized kid I was trying to sell to colleges: There's not going to be a kid on your football program that's going to outwork him."
That attribute is directly related to McKinnon's perceived weakness: He never was very impressive to behold. At just under 5-foot-9, he's 3 inches shorter and 25 pounds lighter than the 49ers' top running back the last three seasons, Carlos Hyde.
When Shackelford first met him, the coach called him "Blow Pop" because his head sat upon a skinny, stick-like frame like a lollipop. Sure, he had quick feet and soft hands, but even as a junior, he was moonlighting on the junior varsity team because Sprayberry High School had bigger, better kids playing quarterback and running back.
"This is a guy who's an NFL running back who was not starting at running back for us," Shackelford said. "Why is that? Because he wasn't our best guy yet."
But at some point between his junior and senior years, McKinnon realized he could use the weight room to catch up to – and surpass – his peers. The click, clack, clank of the gym became the soundtrack to his life. No one was more dedicated, and by college, he was lifting more than the offensive linemen who were more than 100 pounds heavier than him.
Most coaches have to relentlessly prod their players to train harder. Jeff Monken, McKinnon's coach at Georgia Southern, had to do the opposite.
"There came a point in his career in college where we just shut him down," Monken said. "It was, 'Look, you're strong enough,' and frankly some of the squats weights – he was putting up high 500 (pounds) in the squat and he didn't need to go to 600 to prove to us he was strong enough. We wanted him to retain that power but not get him hurt."
Both Shackelford and Monken had the same issue when trying to send McKinnon to the next level: No one was clear on how they should use him.
"I heard this word a bunch: 'He's a "tweener," ' " Shackelford said. "I don't even know what the hell that means. It was, 'He's kind of between a (defensive back) and a receiver and a running back.' "
Monken recruited McKinnon to play quarterback at Georgia Southern, which at the time was a Football Championship Subdivision program. But in the school's triple-option attack, he was more runner than thrower. He attempted 17 passes his entire senior season, for example, while running for 1,050 yards and scoring 12 touchdowns on the ground. He lined up at quarterback, at wing back, at slot and at receiver. In one game early in his college tenure, McKinnon even started at cornerback and came away with two interceptions.
The NFL wasn't quite sure what to make of him. "Jack of all trades, master of none," his pre-draft profile on NFL.com read. "Would benefit from focusing on one position and will require some time to develop."
That report thought he'd be, at best, a seventh-round selection. The Vikings instead took him in the third round but for four seasons mostly used him as a third-down, change-of-pace-type runner.
McKinnon's versatility, however, is precisely why Kyle Shanahan and the 49ers pursued him so aggressively in free agency.
Shanahan was seeking someone who could run between tackles and catch passes equally well, something that Hyde, a more traditional running back, couldn't supply. On many snaps, McKinnon will operate like a conventional tailback. On others, the 49ers will line him up out wide like a receiver and hope the defense sends a 245-pound linebacker to cover him.
"Everyone talks about running back and stuff – they need a new position to name people," Shanahan said. "Because he plays running back and receiver and tight end – he does all that. You use him the same way you use all these positions. He's a very good running back. But he also brings a lot of other stuff to the table."
Back in high school, McKinnon received no offers from Football Bowl Subdivision schools and no interest from the powerful Southeastern Conference teams he grew up watching. That included the University of Florida, where his older brother, Lester Norwood, played.
"I pretty much was on the back burner," he said. "I wasn't one of the top guys that they were giving offers, scholarships to. I was more of a 'we'll wait-and-see' type guy."
McKinnon spent the next four years making those schools sorry for putting him on hold.
In 2011, he was part of a rushing attack that rolled up 302 yards against mighty Alabama. The next year, he ran for 109 yards and two touchdowns versus Georgia.
He saved his biggest blow for last. Georgia Southern closed out the 2013 season at Florida, where McKinnon had sat in the stands watching his brother.
It was what's known in college football as a "money game." Georgia Southern received $550,000 in exchange for what was expected to be a mere tune-up for the Gators' upcoming match against rival Florida State.
The Eagles, however, took the money and ran all over the heavily favored home team. In his final college game, McKinnon rushed for 125 yards and scored the winning touchdown on an outside run with 2:57 remaining.
"I remember watching that and I remember thinking he was the best one on the field," Shanahan said. "When you're the best player on the field for Georgia Southern playing against Florida in Gainesville and they're having a hard time tackling you? That says a lot about the guy."
Shackelford said anyone doubting whether McKinnon is big enough to be San Francisco's lead runner ought to remember what happened in college.
"A lot of people don't think he's a three-down back," Shackelford said. "They think he's a third-down guy. And I'll be very frank with you: It pisses him off. It makes him mad. It's what all the colleges told him out of high school: He wasn't big enough. And I hope everyone says he's not big enough. Because all that's going to do is make him an absolute dog for the 49ers."