“The Saint of Second Chances” is the “baseball” documentary you never knew you wanted.

Heartwarming, amusing, apalling and sad, this story of flawed baseball team owner, promoter/cheerleader Mike Veeck takes us through the ups and downs of a third generation “baseball guy,” and manages to be damned entertaining pretty much start to finish.

It’s a delighful bon bon to throw our way just as the Major League playoffs are about to begin.

Two great documentary filmmakers — Jeff Malmberg of “Won’t You Be By Neighbor,” and Morgan Neville (“Twenty Feet from Stardom”) — team up to tell an intimate, self-effacing story of baseball promotions, “hustling” up attendance through the triumph and tragedy of Mike Veeck, whose cinematic biography is in the best “Everybody loves a comeback” tradition.

Two different “Bill” Veecks — grandfather William and peg-legged pirate of promotions father Bill — owned teams in Chicago over the decades. Bill, the younger, became one of baseball’s great innovators, changing the game during the years he owned Cleveland and St. Louis franchises, and the two times he took over the Chicago White Sox.

Mike Veeck was Bill’s rebellious, perhaps a tad overlooked son who came on board with his father when Bill bought the Sox back in 1975. The film, a docu-drama that has Mike interviewed on camera and agree on camera to “play” his dad in the story, casts Charlie Day as the young Mike, a garage band rocker who gives up that dream and shows up at “the office” in a ironic (symbolic) “Owner’s Son” t-shirt.

We see the kid do every menial job the shoestring operation demands and watch his father hold forth from his “office,” the Bard’s Room Bar inside old Comiskey Park, the home of the White Sox.

Former players like Tony LaRussa remember the legendary, larger than life Bill, who cast a giant shadow son Mike spent much of his life trying to escape.

Bill had “changed” baseball. Mike would, too. From his father, he picked up the principle that their games would be “street theater wrapped around a ball game.” And he’d excel at it.

But as a budding “hustler” and promoter, he’d preside over one of the most infamous “promotions” in baseball history — “Disco Demolition Night” — and spend decades living that down. The guy who invented The Luxury Box viewing experience as a means of raising fast cash to re-sign a free agent they were about to lose couldn’t get hired anywhere.

Malmberg and Neville got Jeff Daniels to deliver a droll, playful narration of the ups and downs of Veck the Younger’s life. After that that ugly “disco” night (a racist, homophobic crowd, brought their by a race-and-gay-baiting DJ, got out of control), we see the trials, the years-long drunk that the love of a good woman ended, the “comeback” that takes us in directions we never expect and the tragedies we don’t see coming.

Sentimental highs include Mike’s St. Paul, Minnesota minor-league team give recovering addict Darryl Strawberry the last of his many “last chances,” one that saw him flower thanks to a teammate/gimmick Mike introduced into the Darryl year with the St. Paul Saints.

The lows include Mike’s last blundered big league gimmick (indoor fireworks at Tampa Bay’s Tropicana Field) and personal losses we don’t see coming.

Neville and Malmberg use their Netflix budget to buy song rights to turn many a sequence into a musical montage, which, along with Mike Veeck’s big laugh, gives “The Saint of Second Chances” a jaunty pace and tone to go with an adorably warm feeling.

Purists may sniff at the “Veeck as in ‘Wreck'” blasphemies committed in the name of jazzing/sexing up the game and the ballpark experience. And the film’s point of view is seriously one-sided, so those purists don’t really have a voice here.

But this “Saint” earns this “Second Chance” thanks to a film sure to warm all but the most horsehide-thick basefaull buff’s heart.

Rating: TV-MA, profanity, alcohol abuse

Cast: Mike Veeck, Charlie Day, Libby Veeck, Night Train Veeck, Darryl Strawberry, Tony LaRussa, narrated by Jeff Daniels.

Credits: Written and directed by Jeff Malmberg and Morgan Neville. A Netflix release.

Running time: 1:33