Bob Stoops will step down after 18 seasons at Oklahoma. (Associated Press)

This story has been updated.

In the eccentric panorama of national college football, Bob Stoops’ retirement Wednesday qualifies for the imaginary Richter scale. It’s jarring. It’s more than the odd timing (these tumbleweed days of early June), the drowsy run-up (his routine recruiting tweets of recent days) or the striking lack of rumblings (in a sport prone to long rumblings preceding departures). It’s the dislodging of bedrock, of the accepted American reality of Stoops at Oklahoma.

It has been Stoops at Oklahoma since last century even as that century has shrunk and shrunk in the rear view. It has been Stoops at Oklahoma since Wednesday, Dec. 1, 1998, when the Sooners decided they could not abide the limited relevance of 23-33-1 over the previous five seasons and fetched Stoops from Steve Spurrier’s staff at Florida, knowing Stoops well after his three seasons directing Bill Snyder’s defense at Kansas State. On the next day, Iowa would hire Kirk Ferentz. In the 18 seasons since, every other top-division coach hired before them veered away for one reason or another, with somber scoreboards most often the main reason.

It was Stoops at Oklahoma when he righted the whole thing to a national title in his second season, Stoops at Oklahoma in three national runner-up finishes and one College Football Playoff (2015) since, Stoops at Oklahoma for so long that those who craved his exit after the 8-5 of 2014 were operating on a haughtiness Stoops himself had reconstructed. He was 38 when he took the job, 56 when he gave it up; a bale of hope when he started, a bale of bedrock when he finished.

He was there, and still there, and still there, all the way to 190-48, for so long that it was understandable Wednesday when chatterbox America reckoned there must be something wrong for this to happen so suddenly. He long since had wedged himself into the ground as much as an oil rig or an Eastern redbud tree. Just Tuesday, he retweeted glee over Oklahoma softball and its fresh national championship. Just Monday, he welcomed back the “Boys of Summer” with a video on Oklahoma Football Move In Day, a capitalized near-holiday.

Just Sunday, he retweeted junior-college defensive tackle Dillon Faamatau’s thank-you to Stoops and Oklahoma coaches for the “amazing” visit, and Tuesday came news that Oklahoma had “flipped” Faamatau from Southern California. Just Sunday again, Stoops retweeted similar thanks from Anthony McKinney, the four-star junior-college offensive tackle. Just last Thursday, he dragged out an exclamation point for getting “a gunslinger from across the border,” and only those who don’t follow college football might have wondered which of the state of Oklahoma’s six borders he meant.

The “gunslinger” was rising high school senior quarterback Tanner Mordecai, from Waco, Tex., with Oklahoma’s 2018 class under typically fine construction using its usual wealth of Texan parts.

And then, over the weekend, Berry Tramel of the Daily Oklahoman reported about Stoops’s Tulsa stop along the “OU Caravan,” a marketing tour. There, Stoops worked up a vigorous defense of the Big 12 Conference, the 21-year-old outfit Stoops won 10 times for Oklahoma (sharing only one of the 10 titles). He extolled the excitement even in a decade when some Americans have pooh-poohed the Big 12, in part for its lack of American baubles such as a football conference championship game.

Besides, the Big 12 championship game will return Dec. 2, with Stoops probably the most likely figure to appear in person.

By Wednesday, here came Tramel again, with news that Stoops had finished. Oklahoma will go to its Sept. 9 rumble at Ohio State — its second game, after opening with Texas-El Paso — with Lincoln Riley as a head coach. Riley, who then will be four days past his 34th birthday, is a two-season offensive coordinator, a former walk-on quarterback at Texas Tech and a congregation member in the crowded church of Mike Leach, the former Texas Tech and current Washington State coach.

Stoops leaves behind a heap of wins and some top-level losses: to Nick Saban at LSU (2003 national-title game), to Pete Carroll at Southern California (2004), to Urban Meyer at Florida (2008), to Dabo Swinney at Clemson in a national semifinal (2015), and back to that psychedelic trick-play bunch from Boise State in the 2007 Fiesta Bowl. He also leaves behind, way in the background, the masterful 13-2 upset of Florida State as a strange, unbeaten, top-ranked, 10 1/2-point underdog in the national title game after the 2000 season, after which Bobby Bowden, in another era, said, “They did a great job of confusing us.”

Seventeen years later, the stable ground had moved, figuratively, in a place so steady for so long, save for all the fracking tremors. It had moved with characteristic weirdness, just after a few amazing recruiting trips through which necessity might have demanded dishonesty (or not). It sometimes does that in this funky business of college sports.