Sources: Initial fear is Giants' Daniel Jones has torn ACL

LAS VEGAS -- New York Giants quarterback Daniel Jones left Sunday's 30-6 loss to the Las Vegas Raiders in the first half because of a noncontact knee injury that could end his season.

The initial fear, sources told ESPN, is that Jones has a torn ACL in his right knee. An MRI has been scheduled for Monday to determine the full extent of the injury, but there is concern that this appears to be a long-term issue. Jones was making his return Sunday after missing the three previous games because of a neck injury.

"Tough. You never want your guys to go down," coach Brian Daboll said. "He's worked really hard to get back. It's unfortunate."

Jones underwent an X-ray at Allegiant Stadium that came back negative. But his fate will ultimately be determined when he undergoes further tests and the MRI in New York.

The Giants' starting quarterback walked through the locker room after the game with no crutches but a noticeable limp. His facial expressions seemed to indicate the situation was not good.

"I'm not going to jump the gun or anything," running back Saquon Barkley said in the somber locker room moments later. "I'm not going to sit here and speak for [Jones]. You don't know until you get an MRI. Pray for him. He knows I got his back no matter what. We got his back no matter what. ... You never know until you have to get an MRI."

The concerning part is the injury occurred without Jones taking a hit. His knee buckled on the final play of the first quarter when he was sacked.

"That's not a good sign," said Giants offensive lineman Justin Pugh, who just recently returned from a torn ACL. "You never want to put the cart before the horse. Let's get an MRI. Let's get pictures of it. I was in his shoes a year ago but let's just hope everything is all right."

In-between quarters, Jones tested it out and remained in the game. On the first play of the second quarter, he fell to the ground untouched in the middle of his dropback and grabbed at the knee. Jones walked to the sideline and went into the blue medical tent for further evaluation. After several minutes, Jones walked under his own power off the field and into the tunnel nearest to the X-ray room at Allegiant Stadium.

"He felt like he buckled," Daboll said of the final play of the first quarter. "And then he was running it off. We went over and talked to him and he said, 'Nah, I'm good.' Then went back in and obviously he wasn't."

Tommy DeVito came into the game in Jones' absence. The undrafted rookie threw for minus-1 yard in place of Tyrod Taylor the previous week against the New York Jets. DeVito went 15-of-20 passing for 175 yards with a touchdown pass and two interceptions against the Raiders.

This has been a nightmare season for Jones and the Giants, coming just months after he signed a four-year, $160 million contract. Jones, 26, was 4-of-9 passing for 25 yards before leaving Sunday's game with this latest injury. He has two touchdown passes and six interceptions in six games this season.

The locker room seemed to see where this was headed. Jones could be in for a long road back to the field.

"It was just tough," said wide receiver Wan'Dale Robinson, who also tore an ACL last season. "Seeing him already, kind of knew everything he had to go through with the neck, just feel like he couldn't catch a break."

The Giants (2-7) are already without backup quarterback Taylor, who was placed on injured reserve Saturday with a rib cage injury. He will miss at least four games. DeVito and veteran Matt Barkley are the only two healthy quarterbacks on the roster. Barkley was signed to the Giants' practice squad this past week. The team is likely to add another quarterback with Jones seemingly destined for an extended absence.

It was the latest punch to the gut in a season filled with a seemingly endless array of them.

"For him to come back from what he just came back from and then have an injury today, I just couldn't think of a worse-case scenario for a guy," Pugh said. "Just devastating. I hurt for him."