A great day for the Giants quickly gave way to a potentially grim future. On Sunday, they got a dramatic 32-31 come-from-behind victory over the Tampa Bay Buccaneers, and quarterback Daniel Jones, starting in place of Eli Manning for the first time, showed poise and promise.

On Monday came word that the team’s superstar running back and offensive engine, Saquon Barkley, would be out four to eight weeks with a high right ankle sprain, according to persons familiar with the magnetic resonance imaging results who weren’t authorized to speak about the injury.

The thrill of a first victory was tempered by the sight of Barkley being helped off the field in the second quarter. He later returned to the sideline on crutches wearing a walking boot. Despite that equipment, he joined the celebrations of the team’s wild victory.