The team acknowledged the inquiry Monday, saying in a statement without naming Rodgers, "We are aware of the NFL's investigation and will have no further comment at this time."
Rodgers then addressed the situation in a tweet Monday night, saying that he wants to "take full responsibility" for his actions.
"I know I have made mistakes and I am willing to do whatever it takes to repair the situation," Rodgers wrote. "The last thing I ever wanted to do was to be a distraction to the Colts organization, my coaches, and my teammates. I've let people down that I care about.
"I made an error in judgment and I am going to work hard to make sure that those mistakes are rectified through this process. It's an honor to play in the NFL and I have never taken that lightly. I am very sorry for all of this. "
Rodgers, a sixth-round pick, is entering the final year of a four-year, $3.4 million contract.
The sportsbook account was opened under the name of an associate of Rodgers, sources said. Approximately 100 bets were placed on the account over an undisclosed amount of time, including on Colts games, the sources said. Most of the bets were in the $25-$50 range, although there was at least one low four-figure bet.
Rodgers started nine games in 2022 and was seen as a likely starter this season following the trade of Stephon Gilmore to the Dallas Cowboys. If Rodgers is suspended, it could press rookie cornerback Julius Brents, a second-round pick in April, into action.
The news comes after a report by SportsHandle.com, which cited an investigation into a Colts player's "pervasive" betting, including wagers placed on his own team. The player was not named in the report, nor did team officials reveal his identity.
An NFL spokesperson, when asked by ESPN for comment on the report, said in a text message that they had "nothing to add."
The Indiana Gaming Commission confirmed to ESPN that it had received "information pertaining to this matter" and was following developments.
"The IGC is not the lead agency on this matter, as it involves alleged violations of a league policy at this point," Jenny Reske, deputy director at the Indiana Gaming Commission, wrote in an emailed statement to ESPN. "We will, however, continue to review information as it emerges to determine what, if any, regulatory actions are necessary."
In April, the NFL suspended five players -- including four from the Detroit Lions -- for gambling policy violations. Lions receiver Quintez Cephus and safety C.J. Moore, as well as Washington Commanders defensive end Shaka Toney, were suspended indefinitely for betting on NFL games. Lions receivers Jameson Williams and Stanley Berryhill received six-game suspensions for betting on non-NFL games from an NFL facility. Cephus, Moore and Berryhill were later released by Detroit.
Last year, then-Atlanta Falcons receiver Calvin Ridley was suspended for the entire 2022 season for betting on NFL games over a five-game stretch when he was away from the team. He was traded to the Jacksonville Jaguars at the trading deadline last November and reinstated in March.
Although the NFL has widely embraced sports betting and has sponsorship deals with sportsbooks, the league explicitly prohibits players from betting on NFL games. Players are also prohibited from placing bets while at NFL facilities.