McAdoo released a statement on his dismissal, per Patricia Traina of Bleacher Report:
McAdoo initially informed Ian Rapoport of NFL Network of the team's decision on Monday. Aditi Kinkhabwala of NFL.com reported word of Reese's ouster, which Mark Maske of the Washington Post confirmed.
Kinkhabwala noted the "irony" of the situation, as she reported McAdoo was not Reese's choice as head coach and he "liked two other candidates more."
Steve Spagnuolo will serve as the interim head coach in McAdoo's absence, while Kevin Abrams will fill in as general manager, per Kinkhabwala.
McAdoo, 40, went 13-15 in his time as New York's head coach. After he led the Giants to an 11-5 record and a playoff appearance last season, the team fell apart on both sides of the ball this year.
Eli Manning has been disappointing and the offense never clicked, despite the addition of Brandon Marshall, who suffered a season-ending ankle injury in early October. Odell Beckham Jr.'s early-season ankle injury was one reason for New York's slow start, and the team never recovered. Beckham later went down with a broken ankle in early October that ended his season.
The Giants' lone win in their first nine games was a 23-10 triumph over the Denver Broncos. An embarrassing 51-17 home loss to the Los Angeles Rams in Week 9 led to a widespread internal evaluation by the team, which included McAdoo's shuffling the lineup on both sides of the ball. Giants ownership gave him a vote of confidence through the remainder of the season following Week 10.
A controversial benching of Manning before Week 13 only alienated the fanbase more. McAdoo sat Manning, who had 210 consecutive regular-season starts for the Giants, in favor of Geno Smith—a player whose peak potential would be to replicate Manning's "down" statistics. Manning had thrown for 14 touchdowns against seven interceptions at the time of his benching, which would be career-best numbers for Smith.
Albert Breer of The MMQB reported Giants owner John Mara's "anger was obvious to those around the organization over the last week" in the wake of Manning's benching. Mara was "furious" over the impact the move had on the "team's image."
Before losing in Smith's first start, there was widespread speculation that McAdoo would no longer make it through the season. On Sunday morning, ESPN's Adam Schefter and Chris Mortensen reported McAdoo could be let go within 24 hours after Sunday's game.
Mara also noted he signed off on a plan to play Manning for one half and hoped to talk McAdoo into being more "flexible." He also hoped Manning's play would make it "impossible to take him out."
With McAdoo gone, Jordan Raanan of ESPN.com, via Schefter, reported Manning will be under center after sitting out Sunday. Despite this, Mara told reporters he wants to see rookie Davis Webb play before the end of the season.