Koda Glover delivers against the Rockies on Sunday at Nationals Park. (Nick Wass/AP)

Monroe, Okla., is home to about 150 people, give or take, an unincorporated municipality in the southeast corner of the state, near the Arkansas border.

Its name comes from the area’s first postmaster, and neighboring towns in Le Flore County trace their origins that way, too. Monroe, like nearby Heavener, like the closest city (Poteau, population 8,500), began with a post office, trading post or railroad station. But history there traces to earlier moments, with the Choctaw nation, with treaties and migration, with all the push and pull that defined those cultural collisions.

Perhaps someday, Monroe’s and Le Flore County’s history also will include a chapter on Koda Glover, the 23-year-old Washington Nationals rookie reliever who is a cultural collision in himself. His name means “Bear” in Cherokee, and after growing up in a town of 150, Glover is now pitching for tens of thousands every night. The tall righty from Monroe is one of the organization’s fastest rising prospects ever and likely a key part of the Nationals’ late-inning arsenal this October — and, the team hopes, for many Octobers to come.

Everyone near Monroe knows the Glovers. Koda’s father, Ray, is a longtime high school baseball coach and coached Koda at Heavener High. Monroe has a K-8 school but is too small for a high school — “the definition of tiny,” said Glover, who therefore had to commute to the high school where his father coached.

Koda Glover works in the ninth inning during his major league debut July 20 against the Dodgers. (Matthew Hazlett/Getty Images)

Ray played college baseball, and his three older sons were good enough to do so, too. Ray’s promising career ended after an injury during his senior year at Southeastern Oklahoma State.

“Only kind of degree I had was to go teach and coach,” Ray Glover, a coach for 35 years, said. “So that’s what I did.”

Koda tagged along to practices and spent hours in the dugout, with baseball as his unofficial babysitter. Because his father was coaching high school ball, he could not hover to oversee Koda’s development. He didn’t have to.

“Any spare time, he played. Koda didn’t go to town. He didn’t run around. He was practicing,” Ray said. “He’s worn out mattresses; he’s worn out old doors — just out in the back, throwing.”

Koda was the best shortstop Ray had ever coached, but former Eastern Oklahoma Junior College coach Craig Price saw something in that arm.

“You could tell he was special, even back then,” said Price, who played against the older Glover boys. “Did I think he was going to play in the big leagues when he was 12? No. But I did when he was 18 years old, and that’s when we recruited him.”

In junior college, he injured the ulnar collateral ligament in his throwing arm and needed Tommy John surgery. He and Ray started thinking about taking groundballs at first base in case his arm did not bounce back. But it did, and several Division I colleges came recruiting.

He ended up at Oklahoma State, where Coach Josh Holliday and his staff encouraged him to start throwing his cutter more, a pitch that sits somewhere around 90 mph and on which he has relied heavily during his brief major league tenure. That cutter, a 98-mph fastball, a change-up some scouts still consider his second-best pitch and a curveball give him a starter’s arsenal. The Nationals considered using him that way but decided he fit better — and could help sooner — in the bullpen.

“He came on the scene quickly for us,” Nationals director of player development Mark Scialabba said. “Immediately, when we saw him, we knew he had a power arm and had a fearlessness from day one. He’s a very confident young man who we moved a little quicker than some of the other draftees last year.”

Quicker than all of the other draftees, in fact, because Glover was one of the first members of the 2015 draft class from any team to play in the majors when the Nationals called him up in late July. He also was the first of their draft choices from the 2013, 2014, or 2015 drafts to make the majors — one of their fastest-rising prospects since Bryce Harper, Stephen Strasburg and Drew Storen.

He finished last season — his first half-season in professional baseball — at Class A Hagerstown, and by this past June, he was at Class AAA Syracuse when the Nationals called on him.

Nationals pitching coach Mike Maddux offers some of his rarest praise when he says Glover “believes in himself.” Asked how he knows that, Maddux explained it simply: “A young guy who shakes the catcher off.”

Glover has done that occasionally during his nine outings, seven of which have been scoreless. He has struck out 10 batters, walked four and allowed seven hits in 11 innings. In the clubhouse, he is quiet, most often turned toward his locker, speaking mostly when spoken to, though so eager to get his work in that throwing partner Blake Treinen teases him about his promptness. But he is neither timid nor out of place there, either.

“He’s a warrior. He’s strong. He’s strong-willed. He’s strong-minded. I can tell he’s brave. He’s not afraid of anything,” Manager Dusty Baker said. “. . . Koda, man, he’s going to come up big. . . . Koda doesn’t act like a rookie.”

Baker believes he has something in common with Glover, who can relate to his heritage after spending time with Native Americans in Wyoming before this season. Baker said he could tell Glover, who said he is part-Cherokee, part-Sioux and a few other tribes, is proud of that heritage.

Glover, who has a bear claw tattooed on his chest and a distinct hairstyle, said his heritage is not a big deal in Oklahoma, where large portions of the population are of Native American descent. But as he traveled for baseball, he became more in tune with that part of his heritage, far rarer in the majors than in Le Flore County, which is following his every move closely.

“Right now, everyone within about — I don’t know — an 80-mile radius of his home town watches the stat ticker to see if he got to pitch,” Price said.

Glover’s father said everyone asks him why he doesn’t seem more excited.

“I don’t know how to act,” Ray said. “It’s crazy.”

His son, transplanted from Monroe to the majors, seems to know exactly what to do, having adjusted little by little from the Heavener High School and Eastern Oklahoma facilities to the far better resources at Oklahoma State — “just a lot of stepping stones along the way,” said Glover, whose next step may carry him into the October spotlight.