Vikings rookie Roc Thomas kept a straight face when describing what he was attempting to do in Saturday’s preseason opener.

“I was trying to get my name out,” he said. “That was the whole goal.”

Then Thomas laughed.

“I’m kidding, man.”

Regardless, it worked. The undrafted rookie running back left a lasting impression in the Vikings’ 42-28 exhibition victory over the Broncos, catching three passes for 102 yards and two touchdowns and rushing eight times for 29 yards.

Thomas is battling Mack Brown and Mike Boone for a spot on the 53-man roster as the third back behind Dalvin Cook and Latavius Murray. He wasted no time in showing his stuff after checking in late in the first quarter.

Thomas caught a 13-yard touchdown pass from Trevor Siemian with 1:36 left in the quarter. Then he took a screen pass from Siemian and sprinted 78 yards to the end zone with 4:59 left in the first half.

“My whole train of thought was go in and just try to get your feet wet, but I got my whole body wet,” Thomas said.

It was an impressive debut for a unheralded back out of Jacksonville State, where he rushed for 1,065 yards as a senior. Thomas spent his first two years at Auburn but didn’t play much before transferring.

“I tell people I’m from Jacksonville State and they say, ‘Florida?’ ” Thomas said. “I say, ‘No, Jacksonville, Alabama.’ ”

But the location of Thomas’ college is better known than his given first name: Racean.

“Maybe like 12 people know that, and that’s my family,” he said. “Or maybe my teachers in high school, and that’s probably it.”

The Oxford, Ala., native got his nickname from his aunt, Lily Thomas, because he was a handful growing up.

“I would cause a lot of trouble,” he said. “Everybody was just calling me ‘Roc’ like a rock because I was a hard-headed kid. I was always running around and hitting my sisters and brothers on the upside of the head. I was bad. I was real bad.”

Thomas insists now that he’s a good guy and the only people he hits are defenders in his way. According to Pro Football Focus, Thomas averaged 2.9 yards following contact on his runs Saturday.

On his long touchdown, nobody got in his way. It was nothing but smooth sailing to the end zone after catching Siemian’s pass three yards behind the line of scrimmage.

“I couldn’t believe it,” Thomas said. “I’m going to take that. That’s money right there. I just saw a lot of green.”

When he got to the end zone, Thomas did a celebratory dance.

“Oh, man, that guy right there has got some juice,” Vikings tackle Rashod Hill said. “We were all impressed by him.”

After the game, Murray sought Thomas out to offer congratulations.

“He looked real good making plays,” Murray said. “This is his first NFL action, so for him to go out there and have a good day, I was happy for him.” Related Articles Gary Kubiak on Vikings’ offensive woes: ‘I’ve got to do a better job’

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The 5-foot-10, 198-pound Thomas is hopeful his receiving ability will help him make the team. He believes he has some similarities to the 5-9, 205-pound Jerick McKinnon, the versatile running back who signed in March as a free agent with San Francisco after four seasons with Minnesota.

“I think (Saturday) was a good showcase of my versatility,” Thomas said. “Coming out of the backfield and catching the ball and running between tackles,”