Playing just four weeks after suffering a knee sprain and three quarters after aggravating the injury, Robert Griffin III reached for a low snap in the fourth quarter of Washington’s first-round playoff game against the Seattle Seahawks in January 2013, stumbling to the ground as his right knee buckled and his career suffered an irreversible twist.

That play, its aftermath and the decisions that contributed to it are the focus of a new memoir to be called “Surviving Washington,” which Griffin announced in a video posted to Twitter on Tuesday. Griffin said the book, which is scheduled for release in August, will detail the “medical mismanagement” he claims he was subjected to during his time with Washington, as well as other issues within the organization, including reports of sexual harassment.

“I’m going to tell you the truth about what happened in that playoff game in [2013] against Seattle,” Griffin said in the video. “I’m going to detail the medical mismanagement that I received during my time in Washington. I’m going to open your eyes to the sexual harassment that permeated the walls of that building, and give you a deep dive into a power struggle between one of the most powerful coaches in all of sports and an owner that many of you want gone.”

Longtime NFL reporter Gary Myers co-authored the book with Griffin. Myers became acquainted with the 2011 Heisman Trophy winner last fall when his literary agent connected him with Griffin, who was looking to write a memoir after he was waived in January by the Baltimore Ravens, effectively ending his NFL career. Griffin, who has expressed interest in playing again, works as an NFL and college football analyst for ESPN.

“I think he felt there are a lot of unanswered questions to his time in Washington,” Myers, in a phone interview, said of Griffin’s motivations for the book, which details his upbringing as a “military kid” and works toward the fateful injury at the end of his rookie season.

“That day changed the trajectory of his career,” Myers said. “He was never the same after that. As hard as he worked to rehab, he just wasn’t the same, and it seems to have been a situation that could have been avoided if things were handled differently.”

Myers, an author of six books, covered that 2013 game for the New York Daily News.

He recalled when Griffin sprained the lateral collateral ligament in his right knee against the Baltimore Ravens in December 2012 and when Griffin returned following a one-game hiatus, using his arm to help Washington clinch its first NFC East title since 1999 with wins over Philadelphia and Dallas. And he recalled when, in the first quarter of Washington’s playoff game against the Seahawks, Griffin aggravated the injury but remained in the game before eventually suffering torn ligaments.

“It didn’t take my decades of experience covering the NFL to realize almost in the first play that he should not be in the game,” Myers said. “It’s still the worst coaching mistake I’ve ever seen. Right up there, but on a different level, with Pete Carroll not running Marshawn Lynch at the end of the Super Bowl against the Patriots.

“Robert is the first to say that he never asked out and was waiting for the adults in the room,” Myers added. “He was 22 years old at the time. He was waiting for this two-time Super Bowl-winning coach [Mike Shanahan] and doctors that included Dr. [James] Andrews, foremost orthopedist in the country. He was waiting for them to say, ‘We don’t think it’s in the team’s best interest or your best interest to continue playing.’ ”

Washington released Griffin in 2016 after he slipped down the depth chart and struggled to recapture the success of his rookie season. He spent a year with the Cleveland Browns and another three with the Ravens.

In the memoir, Griffin will dedicate chapters to his relationships with former Washington coaches Mike and Kyle Shanahan and team owner Daniel Snyder, and another to the organization’s reported culture of sexual misconduct.

“He heard things, didn’t witness … a lot of what came out in those Washington Post stories,” Myers said of Griffin’s experiences and observations on the latter.

Griffin alluded to those supposed revelations in his video, drawing criticism from some who questioned the timing or authenticity of the book’s disclosures.

“That’s a really valid question,” Myers said. “My thought was that during that period of time, the fact that he was playing for another team when those stories came out, he just might not have felt compelled to speak on it at that point, and there might be some things that he wasn’t comfortable talking about at that point — things that I didn’t know about until recently.

“I know that I’m kind of being vague on that, but I think there’s some things that have come out in the book that better answer that question about why he wasn’t comfortable about speaking out on it two years ago. There’s going to be things in there regarding that situation, that wouldn’t have been appropriate for him to discuss two years ago, where he wasn’t comfortable discussing two years ago, but just feels differently now.”