– One moment he is backpedaling to make a one-handed catch with a sack of footballs slung over one shoulder. The next he is zipping out of the end zone to grab a ball from the punt returner before firing a 25-yard spiral down the field.

Blink and you might miss him, but he is sure to grab your attention again soon enough.

Terrell Barnes doesn’t wear a purple helmet or a practice jersey. No, he’s actually one of the guys who get those ready for Teddy Bridgewater and company before the Vikings take the field every day at Minnesota State Mankato.

But the 24-year-old equipment assistant and ball boy extraordinaire, now in his second summer here, has quickly become part of the fabric of training camp, so much that he finally stopped running long enough to sign an autograph and pose for a selfie with another Vikings fan after Wednesday’s practice.

Barnes is beloved by Vikings players, too. They take notice of his attention to detail in the equipment room and his hustle in practice, whether he is scaling a tall chain-link fence like Spiderman to chase down a loose ball or climbing on top of a shed at Blakeslee Stadium to catch Blair Walsh’s successful field-goal tries.

“He does his job 100 percent every day. He gives his all,” wide receiver Jarius Wright said. “You see him chasing punts down out here full speed, running around full speed, doing everything full speed. So that definitely makes you say, ‘I can do my job full speed, too.’ ”

Choosing his career

Barnes has known that he wanted to do this for a living since his high school days in Brown Mills, N.J. He played football there as a freshman and sophomore before giving the game up to focus on wrestling, a sport in which he was an all-county performer. In his spare time, he volunteered as one of his high school’s equipment managers.

After high school, he enrolled at the local DeVry University branch, which was near the campus of Rutgers. He cornered a Rutgers athletics staffer in an elevator and told him of his dream to be an equipment manager there. Because he was not a student, Barnes was not allowed to take on that job. But he impressed the man enough to get hired in the video department.

On his first day, Barnes made his mark with the football staff by sprinting to and from the towering scissor lifts between shooting periods. He kept the intensity up in practice, got admitted to Rutgers and was hired as an equipment manager at Rutgers his first year on campus.

The Vikings brought him on as an intern for the 2014 season. And after they watched him go all-out in practice and do little things like staying late at the end of the day to do laundry to save head equipment manager Dennis Ryan the trouble, the Vikings hired him full-time in March.

“That was a surreal feeling,” Barnes said, squinting in the sun through his signature thick-lensed glasses. “I’m still dreaming in a way, that I’m finally here.”

But General Manager Rick Spielman had a little fun with him first. On Barnes’ final day as an intern, Spielman called Barnes to his office and strung him along, saying that he had to make tough decisions when it came to staffing. Then he stunned Barnes by flashing a smile and revealing that the Vikings wanted to keep him around.

“He’s just one of those young people in our organization that we thought deserved a chance to come on full time,” Spielman explained.

Favorite of players, fans

The biggest component of Barnes’ job is helping to outfit the players, many of them picky, with properly sized socks and the right-colored gloves and cleats. He can rattle off Bridgewater’s shoe size (12β€Š½) and defensive end Brian Robison’s shirt preference (he’s a 2X). Cornerback Captain Munnerlyn’s gear is the easiest (“Me and Captain are the same size”).

But as the fans in Mankato have noticed, Barnes is fascinating to watch dart around in practice.

Barnes, who was equipped with a pedometer during Wednesday’s practice, runs more than 4 miles in a typical two-hour practice. He was on the move for about 60 percent of Wednesday’s practice. And he was clocked at 21.1 miles per hour while chasing one errant pass that skidded out of the end zone.

Since the start of training camp 2½ weeks ago, Barnes, who is known to devour food like a big offensive lineman, has dropped 10 pounds in these steamy summer afternoons.

He has bonded with Bridgewater, in particular, and not just because he is the keeper of Teddy’s two gloves. He dunks footballs in a bucket for Bridgewater’s “Wet Ball Wednesday” drills and sometimes runs routes for the quarterback before practices and games.

“We played Chicago, home game, last game of the year and it’s freezing outside and he’s out there running routes with no shirt on,” Bridgewater said. “Those types of things, you love that about him.”

Barnes believes he got his endless energy from his late father, Timothy. He also listens to old-school music like Ace of Base and Billy Joel to get fired up for camp practices.

Barnes claims that he is trying to learn how to slow down every now and then. But with the Vikings trying to lay the foundation of a playoff team here in Mankato, there’s no time for it now.

“I get mad when I mess up trying to run after a ball or even on the inside when I get a player’s size wrong. I take it to heart,” Barnes said. “[I’m] trying to get better every day so I can help these guys win.”