“I think he was better able to showcase what he could do once we solidified the offensive line,” Shurmur said. “I think that’s a fair assessment.”

As for how he planned to assess Manning’s performance amid the swings in fortune throughout the season, Gettleman was less effusive. He said he would watch film “until my eyes bleed.”

Manning has a full no-trade clause, and cutting him would incur a sizable hit to the Giants’ salary cap. Nevertheless, Gettleman said, “everything is on the table for us.”

Gettleman executed an extensive roster overhaul this season, his first as the team’s general manager. But the Giants still finished last in the N.F.C. East, leaving them with the No. 6 overall pick in the coming draft.

This year’s class is not expected to contain the same caliber of quarterback prospects as last year, when the quarterbacks Baker Mayfield, Sam Darnold, Josh Rosen and Josh Allen all went in the first 10 slots of the draft. Still, Gettleman defended his decision to draft Barkley, a running back, with the second overall pick in 2018. Barkley ran for 1,307 yards, a Giants rookie record, and added 721 yards receiving.

“If I was in that situation 100 times, I’d draft him 100 times,” Gettleman said of Barkley.

His assessment of the 2019 draft options remained the same as a year ago, he said, but he did not rule out selecting a quarterback. The Giants did select a quarterback in the fourth round last summer, Kyle Lauletta, who struggled in his lone appearance of the season, going 0 for 5 with one interception during the second half against Washington on Dec. 9.

“You’re going to take the best player available,” Gettleman said. “You start reaching, you’re going to get in trouble.”