In 2,600-plus word investigative piece published Thursday, the New York Times contends that concussion research conducted by the National Football League is more flawed than previously known. The story also stated that the NFL has big ties to Big Tobacco for its strategy in handling, and presentation of the data.

After the early retirement of several of its high-profile stars from concussions, the NFL formed a committee in 1994 that, through its research, played down the danger of head injuries. The report was based on concussions diagnosed by team doctors over a six-year time period (1996-2001).

Physicians brought in at a later date said the research had relied on faulty analysis.

The NFL has stood by its research since.

But confidential data obtained by the Times revealed that more than 100 diagnosed concussions were left out of the studies — including career-ending injuries suffered by former star quarterbacks Troy Aikman (Cowboys) and Steve Young (49ers).

League officials acknowledged to the Times “the clubs were not required to submit their data and not every club did.’’ That should have been made clearer, the league said in a statement, adding that the missing cases were not part of an attempt “to alter or suppress the rate of concussions.’’

A number of retired NFL players have compared the NFL’s handling of its health/head injury crisis to that of the tobacco industry, which was notorious for using questionable science to downplay the dangers of cigarettes, according to Times. The NFL strongly disagreed, saying it has no connection to Big Tobacco. According to the Times, records show that the two businesses share lobbyists, lawyers, and consultants.

In 2013, the league agreed to a $765 million settlement with retired players who had contended league officials of a coverup. There is an ongoing appeal.

The NFL responded with a 2,500-word rebuttal on Thursday afternoon, contending that the Times’ story “is contradicted by clear facts that both refute the thesis of the story and each of its allegations’’ and “the studies never claimed to be based on every concussion that was reported or that occurred.’’

A re-start for RG3

Robert Griffin III is getting a chance to revive a career that once seemed unstoppable.

One of the NFL’s brightest and flashiest stars just a few years ago, Griffin signed Thursday with the Cleveland Browns, a franchise on a perpetual mission to find a quarterback.

Griffin hasn’t been the same since his dazzling rookie season in Washington in 2012, when RG3 — possessed with a rocket arm, a tailback’s speed and endless swagger — burst onto pro football’s stage. The Browns, who tried to trade up and select Griffin four years ago, believe he can still lead on and off the field, and they’re giving him a chance to revive his career and win their starting job. ‘‘I'm just excited to come in and compete,’’ Griffin said. ‘‘Nothing’s ever been given to me in my life, so I just want to go out and compete with the guys and grow with this team. I feel like that’s all I'm really focused on. I cherish the opportunity to get another chance to play this beautiful game.’’

Griffin met last week with new Browns coach Hue Jackson, who was impressed by the 26-year-old’s candor and eagerness to begin anew.

‘‘He brings starting experience to our team and organization,’’ said the coach. “He’s a young, athletic, talented passer and he’s really just starting out in this league.

“Just like every player on our team, Robert will have to earn every opportunity he gets. He will compete with the rest of the quarterbacks on our roster and he helps improve our QB room, which was one of my goals upon taking the job.’’

‘‘We are looking forward to working with Robert, as well as the rest of the quarterbacks on our roster. We have a lot of work to do to prepare to be the best QB room in the NFL and we look forward to the challenge that lies ahead.’’

Cleveland has started 24 quarterbacks since 1999 and is expected to take one with the No. 2 overall pick in this year’s draft. That rookie — possibly California’s Jared Goff or North Dakota State’s Carson Wentz — will compete with Griffin, the second selection in 2012. Jackson and other members of the Browns attended Wentz’s pro day Thursday in North Dakota.

The Browns recently released troubled quarterback Johnny Manziel, who they once thought would solve their problems.

They also have quarterbacks Josh McCown and Austin Davis on their roster, but as is always the case with that position in Cleveland, nothing stands still.

After winning the Heisman Trophy at Baylor, Griffin was taken in the draft just after Andrew Luck was plucked by the Indianapolis Colts. The Browns attempted to swing a deal to move up and get him but were outbid by the Redskins.

Griffin took the nation’s capital by storm. He led the Redskins to the NFC East title and was named the league’s top offensive rookie. It didn’t take him long to become one of American’s most celebrated athletes and there seemed no limit to what he could accomplish. Griffin, however, sustained a significant right knee injury in a playoff game against Seattle and things would never be the same.

The indelible image of Griffin lying face down on the turf is one that will haunt Redskins fans for years. In a way, it symbolized what might have been.

Griffin underwent reconstructive surgery, but there was little he could do to fix a fractured relationship with then-Washington coach Mike Shanahan. Griffin wound up being benched at the end of his second season, and he missed a big chunk in his third year after dislocating his ankle.

When the Redskins placed the nonexclusive franchise tag on Kirk Cousins last month for $20 million, Griffin, who went 14-21 with 40 touchdown passes as a starter, was let go with little fanfare.

Laurinaitis a Saint

Released after starting every game the past seven seasons at middle linebacker for the St. Louis Rams, James Laurinaitis is highly motivated after inking a three-year deal with the Saints. ‘‘Nobody likes to be fired and that’s essentially what it is — you got fired,’’ he said in a conference call.’’ . . . The Jets are bringing back linebacker/special teams whiz Erin Henderson on a two-year deal. He played every game last year after missing the 2014 season . . . The Falcons re-upped eight-year linebacker Philip Wheeler on a one-year deal . . . North Dakota State QB Carson Wentz was dazzling in his pro day showing in Fargo, N.D., connecting on all but two of his 65 throws. The FCS star is projected by some as the top quarterback in the NFL Draft.