One of the great mysteries of the Cleveland Browns season is that they are 4-5 and feeling good despite having a near non-existent running game.

The team’s leading rusher has 262 carries and averages 2.6 yards per carry -- so what the heck?

Joe Thomas shrugs. The perennial Pro Bowler says it’s not a mystery.

“I’m looking at today’s NFL,” Thomas said in a recent conversation. “And I’m just not sure there’s a place for a running back anymore.”

Say what? Not a place?

“Fifty throws is the average,” Thomas said. “You get a guy who gains 100 yards, whoop dee do. It doesn’t win you games anymore.”

Is a sound running game a major key to success in the NFL? Not at all, Browns offensive lineman Joe Thomas said. AP Photo/Paul Spinelli

This from a guy who played in college at Wisconsin, the ultimate run team?

“If you’re a defensive coordinator and you give up a 100-yard rusher, you don’t really care,” he said. “It really doesn’t translate into winning many games.”

To repeat: A 100-yard back “doesn’t translate into winning many games.”

But, Thomas was told, since 1960, teams that have a back that carries 20 or more times in a game win 72 percent of the time.

“That’s simple,” he said with a smile. “They’re ahead so they run. I think it’s simple.”

Thomas asked his own question: When’s the last first-round running back other than Adrian Peterson to turn out?

Here are the first-round running backs since Thomas joined the league in 2007:

--2013: None

--2012: Trent Richardson, Doug Martin, David Wilson

--2011: Mark Ingram

--2010: C.J. Spiller, Ryan Mathews, Jahvid Best

--2009: Knowshon Moreno, Donald Brown, Chris Wells

--2008: Darren McFadden, Jonathan Stewart, Felix Jones, Rashard Mendenhall, Chris Johnson

--2007: Adrian Peterson, Marshawn Lynch

The best and most consistent and most dependable have been Peterson and Lynch -- but Lynch is successful with his second team, having been traded.

“You have to have soembody who’s a once-in-a-generation talent like Adrian Peterson to really be a difference maker in the game,” Thomas said. “But you get one Josh Gordon, you throw him a jump ball in triple coverage and he goes up and catches a touchdown, you win the game. That’s one guy, one play. He can do that three times in a game. Calvin Johnson. You can go down the list of guys like that who are game-changers. A.J. Green.

“You have to change the entire defense to try to take somebody like that out of the game. And the running game is so hard. Because first of all you have to have six, sometimes seven guys blocking perfectly up front. One mistake and it’s a tackle for a loss. So you have to have seven victories. And then you have to have a RB beat a safety. Today’s safeties are pretty good.”

Thomas also pointed out that offenses are getting more sophisticated at giving the quarterback the extra second he needs to make the throw. Colin Kaepernick’s fakes, he said, freeze a defense for a second.

It would also explain why the Browns have won games when they got good quarterback play and lost when they didn’t.

“That’s why you see quarterbacks, you see the value on those guys going through the roof,” he said. “Mid-level quarterbacks get $20 million a year year because they’re that important. And those receivers are going to start going that way, too.

“And the running backs, unfortunately for them they just don’t have a place in this game anymore like they used to.”

To the point that Thomas said he wouldn’t draft a running back in the first round.

The starting point for this conversation? Why did Thomas think Richardson did not work out in Cleveland?

“I’m not gonna throw stones at a guy that’s not on the team anymore,” Thomas said. “But it’s hard to say it didn’t work out because we got a first-round pick for him. So obviously someone thinks he’s pretty good. I think it comes down to production wasn’t great here, so they felt a first-round pick would be a good trade.

“And, I’m sure in today’s day and age, the value on running backs is down.”