Adrian Peterson has beaten the odds before. Now, they might be 100-1 against him.

The Vikings’ star running back scored on his first carry of the 2013 season, a 78-yard touchdown run at Detroit. He has vowed to do it again on his first attempt in Sunday’s regular-season opener at St. Louis.

“I might as well speak it,” he said Thursday. “Touchdown. First run.”

After Peterson’s declaration, the Pioneer Press contacted Kevin Bradley, sports book manager for the online betting site Bovada.lv, to see what sort of odds Peterson is facing scoring on his first carry against the Rams. Bovada offers plenty of what Bradley called “exotic” proposition bets.

“This is interesting because you obviously don’t know where (the Vikings) are going to get the ball (on their first possession),” Bradley said Friday. “You don’t know whether they’re going get a pick or a fumble early in the game and then they are on the 10-yard line, or they could be on their own 10.

“I would say that we would probably put it at somewhere around 50-1. But the true odds are probably closer to 100-1. But because of the uncertainty of where they’re going to get the ball, I would probably offer it at 50-1.”

Bradley wants to do more research but said he is considering offering that Peterson proposition on Bovada’s site before Sunday’s noon kickoff.

“Whenever there is a story like that in the media, every week we’ll put up something on these story lines that are going on in the NFL,” Bradley said. “So something like that are things we’ve put up on the site. Who knows? Maybe I’ll offer it on the site.”

Peterson already has proposition bets on Bovada’s site. They include the over-under on his rushing yards for the season at 1,350 and for his total touchdowns at 12-1/2.

The running back has beaten the odds plenty, most notably in 2012. After suffering a torn ACL in 2011, he came back to rush for 2,097 yards, second-most in NFL history.

In large part because of that injury, Peterson hasn’t had a preseason carry since 2011. That, too, has added intrigue to his first regular-season runs.

Peterson’s vow to score on his first carry at St. Louis came after he had talked about last year’s touchdown at Detroit. Peterson said he had told some teammates early in the week that he would “take it to the house” on his first attempt, although he didn’t then make a public declaration.

While Peterson had to go 78 yards against the Lions, he was told his task would be easier Sunday if the Vikings were to recover an early fumble at the Rams’ 1.

“I like that scenario,” Peterson said. “I like that one. I like the odds better.”

Follow Chris Tomasson at twitter.com/christomasson.