The Giants hired former Lions general manager Martin Mayhew as director of football operations and special projects. Mayhew replaces Matt Harriss, who had been the Giants’ director of football operations before he was hired by the Lions as vice president of football administration last month.

Mayhew, 50, will “work closely with assistant general manager Kevin Abrams on all aspects of the salary cap, CBA compliance and player contract negotiations,” the Giants said in announcing the hire Thursday. “He will also handle special projects as assigned by general manager Jerry Reese.”

Mayhew is the first announced change to the front office this offseason. When the season ended, Reese said the team would “evaluate our personnel staff and see if there need to be any changes made there.” It’s unclear what role Mayhew will play in scouting or personnel decision-making, and whether those might fall under any “special projects.”

Mayhew was with the Lions for 15 years and was GM from 2008 until he was fired in November. He does not have a background in scouting, having joined the Lions as senior director of football administration/staff counsel. He was promoted to senior vice president of football administration/legal affairs in February 2003, and in October 2004 he was appointed senior vice president and assistant general manager.

He does have experience as a player, though, having played nine seasons in the NFL as a cornerback in Buffalo, Washington and Tampa Bay. He was a starter on Washington’s Super Bowl XXVI champion.

Tuck retiring as Giant. A week after announcing his retirement, Justin Tuck announced plans for a comeback. For one day, anyway.

The former defensive end said Thursday that he will sign a ceremonial one-day contract with the Giants next month to retire officially as a member of the organization for which he played nine seasons and helped win two Super Bowls. He made the announcement on a Giants.com broadcast.

advertisement | advertise on newsday

“We can’t do it yet because the league [year] doesn’t open until the second week of March,” he said. “So for all the Giants fans out there asking me am I going to retire a Giant — absolutely I am.”

Tuck spent the last two seasons with the Raiders after the Giants did not make him a substantial offer to remain following the 2013 season.