The work of two skilled reporters, Tim Elfrink and Gus Garcia-Roberts, “Blood Sport” has some juicy new revelations about the Alex Rodriquez steroid scandal. Undoubtedly, the biggest of these is that in 2007, a year that saw the Yankee slugger produce some of the best numbers of his career and earn his third American League most valuable player award, Rodriguez was using the powerful anabolic steroid testosterone — with the full endorsement of Major League Baseball’s testing program, via a “TUE,” or therapeutic use exemption.

This bombshell is certain to bring down more criticism on both Rodriguez and MLB, with its checkered history with drug-testing. The TUE, per the sport’s drug policy, was approved by a private physician, a doctor in North Carolina serving as an “independent program administrator.” But as MLB Executive Vice President Rob Manfred pointed out in a 2013 arbitration hearing — the leaked transcript of which provides the bulk of this book’s revelations — “the most likely cause of low testosterone requiring this type of therapy would be prior steroid use.”

Rodriguez, it seems, would have done anything to maintain his spot atop baseball, and “Blood Sport” is riveting when it hews closely to the twin entities of its subtitle: A-Rod and Biogenesis, the latter being the Florida-based anti-aging clinic, operated by a schemer and wannabe doctor named Anthony Bosch, that supplied Rodriquez slugger with his drugs. The Rodriguez-Bosch dynamic is a fascinating one, as both are profoundly flawed men who share elements of their Miami backgrounds, not to mention narcissism and a capacity for malfeasance in the name of self-preservation.

The story of Rodriguez’s alliance with Bosch — and their eventual falling-out, with disastrous consequences for both — is a tragicomedy filled with characters straight out of a Carl Hiaasen novel: fake doctors, ex-cons, small-time grifters and a shady tanning-bed repairman whose theft of some Biogenesis documents set in motion much of the legal drama that ensued. The image of Bosch, the fake doctor, injecting Rodriguez in a Starbucks bathroom is particularly unforgettable.

Unfortunately, that detail is one of many juicy tidbits from the book that had already appeared in the newspapers. The same goes for the unsavory lengths to which MLB went — for example, paying informants and obtaining stolen documents intended for a state investigation — in its zeal to nail A-Rod, who is now sitting out a season-long suspension. On top of that, the authors faced an unenviable task in their quest for literary relevance: 16 years after the steroids-tainted home-run duel between Mark McGwire and Sammy Sosa, 10 years after the San Francisco Chronicle broke the story of the BALCO steroids ring, and five years after Sports Illustrated first linked Rodriguez to steroid use, does anyone really want to read another book-length examination of performance-enhancing drugs in baseball?

‘Blood Sport: Alex Rodriguez, Biogenesis, and the Quest to End Baseball's Steroid Era’ by Tim Elfrink and Gus Garcia-Roberts (Dutton)

By now, with Major League Baseball’s drug-testing program having gone from nonexistent to the toughest in all of sports, and with three well-received books about steroids in baseball already on bookshelves — Jose Canseco’s lurid 2005 memoir, “Juiced”; Howard Bryant’s 2005 exhaustive history, “Juicing the Game”; and Mark Fainaru-Wada and Lance Williams’s 2006 best-selling exposé of the BALCO scandal, “Game of Shadows” — there is a tangible sense of steroids fatigue among baseball observers, both inside and outside the sport.

You can’t fault Elfrink and Garcia-Roberts for trying. For one thing, they had a compelling, blockbuster story on their hands, one they had spent months reporting on for their respective newspapers, the Miami New Times and Long Island’s Newsday. And as for relevance, well, given the way the Biogenesis scandal dominated ESPN’s “SportsCenter” and the front pages of newspapers throughout 2013 and into early 2014, clearly somebody was still interested in the sordid tale of baseball and steroids — at least when it pertains to A-Rod, perhaps the world’s most disliked and dislikable athlete.

Unfortunately, the inherent dilemma of turning a well-reported newspaper series into a book — either rehash a story that has already been told or dive deeper to provide additional context at the risk of veering too far away from the narrative — proved too much at times for this project to overcome.

In their attempts to deepen the narrative with historical and biographical context, too often the authors either dredge up old, well-known tales of steroids scandals past or plunge into esoterica. One especially useful bit of context, however, is the reminder that the 2007 investigative report by former senator George Mitchell that exposed dozens of steroid-users in the sport contained a prophetic warning, largely ignored at the time, about the many anti-aging clinics in Florida that were dishing out human growth hormone, or HGH, under the radar of regulators and law enforcement.

After a Cast of Characters — helpful as a resource to the reader, given the many threads running through the book — and a prologue that begins with the seeds of the Bosch-Rodriguez estrangement, not until Page 169 do we get the fateful first meeting of our two protagonists, and not until Page 185 does Biogenesis, the clinic, enter the narrative.

The last 100 pages, even if the story was already told in the newspapers, are pure gold, detailing the seedy battle, waged with lawyers and money, between A-Rod and his former drug source; and the book ends with an epilogue that reads like an eloquent essay on how the financial incentive to dope ensures that players, from the elite sluggers to the fringe big-leaguers, will keep trying to beat the system.

So if you think the authors of “Blood Sport” are going up against a public racked by a case of steroids fatigue, imagine what the authors of the next steroids exposé will face.

Dave Sheinin is a Washington Post sportswriter and the author of “RG3: The Promise.”

BLOOD SPORT

Alex Rodriguez, Biogenesis, and the Quest to End Baseball’s Steroids Era

By Tim Elfrink and Gus Garcia-Roberts

Dutton. 461 pp. $27.95