CHICAGO -- The Bears were forced to cancel their organized team activity practice originally scheduled for Tuesday after having live contact during practices in May, a source confirmed to ESPN.

According to a source, NFLPA representatives were present at Halas Hall last month for a practice, which was a part of their regularly scheduled visits to each team, and witnessed on-field contact. The NFLPA issued a warning and continued to monitor Bears practices by requesting practice video and saw more contact in practices after the warning.

According to the NFL's Collective Bargaining Agreement, which is agreed upon by the players' association and team owners, live contact is prohibited during offseason workouts. For that reason, the Bears were docked an OTA practice in violation of league rules.

This is the first offseason program being run by first-year head coach Matt Eberflus and general manager Ryan Poles.

The Chicago Tribune was first to report the Bears' offseason misstep.

The team sent an email to reporters on Monday night addressing a change to this week's OTAs schedule with media access being moved from Tuesday to Wednesday. No explanation was offered by Bears public relations behind the altered schedule.

Chicago is in its last week of OTA practices before hosting its three-day mandatory minicamp next week.

ESPN's Dan Graziano contributed to this report.