Beckham has been dealing with a quadriceps injury and missed Sunday's 40-16 win over the Washington Redskins. He didn't participate in practice Friday for a second straight day.
"He just can't go. No setbacks. He just can't go," Shurmur said.
Beckham didn't practice Thursday and went off-site for further evaluation, saying the tests were a double-check to make sure there had been progress more than anything else. He had participated in the individual portion of practice the previous day.
The Giants (5-8) haven't been mathematically eliminated from playoff contention with three games remaining in the season. They have an outside shot -- less than 1 percent according to FPI -- and don't appear to be considering putting Beckham on injured reserve, which would end his season.
"No. I think it's a day-to-day thing. ... He's got a quad thing going on," Shurmur said.
Beckham's absence against the Titans will mean an altered role for Sterling Shepard and more playing time for Corey Coleman and Russell Shepard. Coleman played the second-most snaps among Giants wide receivers on Sunday and had two receptions for 43 yards. Russell Shepard had a touchdown catch.
Sterling Shepard becomes the Giants' top target.
"Naturally I think that happens because Odell gets the bulk of them whenever he's in there," Sterling Shepard said. "So there is definitely room for everybody to spread the ball around. Yeah, I look forward to it."
Beckham sustained the injury on the final play of a Nov. 25 loss to the Philadelphia Eagles. He played the next week against the Chicago Bears and did not appear on the injury report until after practicing the following Friday.
He was a limited participant in practice Wednesday when he took part in individual drills. But after sitting out the next day and going for another examination on the quad, Beckham thought he wouldn't know until Sunday if he would be able to play this week against the Titans. The following day he was ruled out by the Giants.
When asked on Thursday if he was dealing with a bruised quad, he wasn't sure how to describe the injury. It had been mentioned as a bruise or even that he had blood buildup in the quad.
"I don't know. It's like saying I broke my leg, but you really fractured it. It's a choice of words," Beckham said Thursday. "Whatever you want to call it, s--- ain't right."
Beckham has 77 catches for 1,052 yards and six touchdowns this season. He insists he'll be back whenever he's cleared. He mentioned playing injured and in pain against the Rams and Ravens during the 2016 season.
"Whenever it's better, I'll definitely be out there," Beckham said. "I don't even like missing practice. So whenever I can run, I'll be running."
It won't be this week.