The Giants could use a big body on defense to replace Dalvin Tomlinson, the big body they lost on defense in free agency. That is why Danny Shelton, who qualifies as a big body, paid a visit Monday, The Post confirmed, and why it took him almost no time at all to agree to a one-year contract.

Shelton, 27, is a 335-pound (some estimates have him as high as 345 pounds) defensive lineman who is supposed to specialize in stopping the run. Tomlinson, a four-year starter at defensive tackle, priced himself out of the Giants’ market in free agency and signed a two-year, $22 million deal with the Vikings, creating a void on the three-man line. Leonard Williams and Dexter Lawrence return as starters but an anchor is needed between them.

The Giants re-signed Austin Johnson and the 26-year old is an option. He played in all 16 games in 2020 after starting 13 games in four years with the Titans. Johnson is 313 pounds. Shelton is a heftier option.

In 2015, Shelton was the No. 12 overall pick in the NFL draft, taken by the Browns. He did not live up to that lofty draft status and, after three years in Cleveland, he was traded to the Patriots, where he stayed for two seasons and won a Super Bowl. In his best season, Shelton had 61 total tackles and three sacks for the Pats in 2019, when Joe Judge was the special teams coordinator in New England, so a connection is there.

In 2020, Shelton signed a two-year, $8 million deal with the Lions, started 12 games and was released two weeks ago with a failed physical designation. Shelton suffered a triceps injury in the season finale. The Lions saved $4 million on the cap with the release. It is not difficult to see why Shelton was a one-and-done in Detroit. His defensive grade of 51.5 by Pro Football Focus was easily the worst of his six-year career and his run-stopping grade was actually lower than his pass-rush grade.

The Giants met with Shelton and determined he is healthy and a scheme fit. Much of the conversation was with Patrick Graham, the defensive coordinator, and Sean Spencer, the defensive line coach. Graham, who was on hand at State College, Pa., last Thursday for Penn State’s Pro Day, stayed back at the team facility Monday to meet with Shelton, rather than attend the University of Miami Pro Day.

NFL teams are limited to three representatives for these Pro Days. The Giants’ contingent in Miami — Judge, director of college scouting Chris Pettit and Tim McDonnell, the assistant director of player personnel — had some interesting defensive players to observe. Edge-rusher Gregory Rousseau should be in play for the Giants at No. 11 in the upcoming draft, and Jaelan Phillips could be as well. Rousseau in 2019 had 15.5 sacks and 19.5 tackles for loss for the Hurricanes and opted out for 2020. Phillips in his one year at Miami had eight sacks and 15.5 tackles for loss last season.

Rousseau at 6-6 ¹/₂ and 266 pounds is a prototypical defensive end/outside linebacker in terms of stature, and that he ran 4.68 in the 40-yard dash on Monday fuels the fire for his NFL potential. Phillips, though, is 6-5 and 260 pounds and he clocked in at a blazing 4.56. He started his college career at UCLA before moving onto Miami. Phillips had a rough stay at UCLA, with injuries to both ankles and badly fractured wrist from a moped accident. He actually retired from football while at UCLA after recurring concussion issues, sat out the 2019 season while transferring and then filled in for Rousseau in 2020 with a strong showing for the Hurricanes.

There are scouts who view Phillips as the best pure pass rusher in the draft, but his medical history must be explored.

The Giants addressed their need for a starting wide receiver, signing Kenny Golladay, and filled their need for a starting cornerback, signing Adoree’ Jackson. This free-agency spree allows the Giants to use their six picks in the NFL draft, and especially their first-round selection, on the player they believe has the greatest potential, having already paid to improve their two greatest areas of need.