Michael Boley -- NFL Star Secretly Arrested for Child Abuse

Ex-New York Giants linebacker Michael Boley was quietly arrested for child abuse back in February ... 3 days after he was cut by the team ... TMZ has learned.

Boley -- a starting linebacker in Super Bowl XLVI -- had been under investigation in Alabama for a 2011 incident involving his son, who was 5 years old at the time.

The details of the alleged abuse are unclear, although sources tell us the allegations were of a physical nature and NOT sexual abuse.

Here's what we know ... Boley's case was scheduled to go in front of a grand jury in February 2013 ... but before that got under way, the 30-year-old NFL star struck a plea deal with prosecutors.

Court officials in Etowah County, AL tell TMZ ... Boley pled guilty to child abuse -- and in exchange, he was ordered to enroll in a pre-trial diversion program and upon completion the charge would be dropped.

Boley was also required to turn himself into authorities. He was booked on February 8, smiled for a mug shot and was released from custody later that day.

Seems the NY Giants were hip to Boley's legal issues ... 'cause he was unexpectedly cut by the team on February 5 ... 3 days before Boley turned himself in to authorities. Boley is currently a free agent, on the hunt for a job.

A rep for Boley had no comment -- but sources connected to the NFL star tell us Boley plans to comply with the terms of the plea deal.

5/3 -- Boley's agents have released a statement saying, "Mr. Boley is dealing with a personal matter that allegedly happened nearly two years ago. Michael has been and always will be a loving and supportive father to all of his children."