A three-team parlay that included an Arizona Cardinals game led the NFL in part to suspend Cardinals defensive back Josh Shaw for violating the league's gambling policy, multiple sources told ESPN.

Shaw, who has been on injured reserve since August and has not played since signing with the Cardinals in March, made the parlay bet on Sunday, Nov. 10, at a Caesars sportsbook in Las Vegas, according to the sources. The bet was on the second halves of three Week 10 games, the sources said, and included the Tampa Bay Buccaneers, who were leading the Cardinals 17-13 at halftime. The Buccaneers were 1-point favorites for the second half. They failed to cover the second-half spread but went on to defeat the Cardinals 30-27. Shaw's bet lost, according to the sources.

The NFL announced Friday that Shaw is suspended through at least the 2020 season for betting on NFL games on multiple occasions. The league said its investigation found no evidence that Shaw used inside information to make his bets nor that any games were compromised. Parlay bets, because they require multiple correct picks, typically have not been associated with point-shaving or game-fixing schemes.

The NFL declined to comment on specifics of the wagers, with a league spokesman saying that neither the type of bet nor the games involved matter in terms of the league's gambling policy.

Shaw, who is out with a shoulder injury, has not been around the Cardinals this season. ESPN's Adam Schefter reported that Arizona was not aware that the NFL was investigating one of its players before Friday's announcement, which was preceded by a leaguewide memo emphasizing the gambling policy and penalties for violating it.

"If you work in the NFL in any capacity, you may not bet on NFL football," commissioner Roger Goodell said in the release announcing the suspension.

Nevada gaming regulations require sportsbooks to "take reasonable steps" to avoid accepting or paying any wagers made by or on behalf of an official, owner, coach or a participant or team in the event involved with the bet. A version of the regulation has been in place since 2001.

According to gaming industry sources, Caesars contacted the Nevada Gaming Control Board on Nov. 10, and subsequently the NFL, shortly after discovering Shaw had placed the wager.

Shaw was open about his line of work when filling out his application for a betting account with Caesars, even listing "professional football player" as his occupation, the sources said.

"As a matter of policy, we do not confirm or deny that an individual is a Caesars customer," Richard Broome, executive vice president of communication for Caesars Entertainment, said in a statement to ESPN.

In January, the NFL announced a partnership with Caesars Entertainment, making the company the league's first official casino partner. The partnership, however, does not include sports betting initiatives.

Shaw's suspension is the first reported violation of a major professional league's gambling policy since a 2018 ruling from the U.S. Supreme Court that opened a path for states to authorize sports betting. Since the ruling, legal sportsbooks have opened in a dozen states outside of Nevada.

The NFL includes language in player contracts regarding the gambling policy, and the NFL Players Association has increased its efforts to educate players on the new sports betting landscape since the Supreme Court ruling.

In 1996, Jon Stark, a rookie quarterback for the Baltimore Ravens, was suspended for gambling after the NFL received an anonymous tip. Stark never played in an NFL game.

On a more high-profile level, Baltimore Colts quarterback Art Schlichter was suspended in 1983 for betting on NFL games, and in 1963, Paul Hornung of the Green Bay Packers and Alex Karras of the Detroit Lions were banned for an entire season for betting on NFL games. Both were reinstated the following season.

Shaw is represented by Elite Athlete Management. Messages left with the agency were not immediately returned.