Flowers, who did not participate in the voluntary veteran minicamp on April 24-26, reported for work Monday at the team's training facility, NFL Network's Kimberly Jones confirmed. ESPN reported the news first.
He has started 46 games on his career, but the signing of Nate Solder during free agency signaled a change along the offensive line with the move of Flowers to right tackle.
The Giants did not exercise a fifth-year option on Flowers, who has struggled on the field during his time in New York, and he now enters the final year of his rookie contract.
New York will hold organized team activities on May 21-22, May 24, May 29-31 and June 4-7. A three-day mandatory minicamp is scheduled for June 12-14.