He’s out sight and out of mind for Giants fans.

But Odell Beckham Jr., despite being shelved for the season since he blew out his left ankle in the Giants’ loss to the Chargers on Oct. 8, has remained a highly visible and powerful motivating presence to his teammates behind closed doors.

Beckham, according to his fellow receivers when asked by The Post on Tuesday, has been as valuable a teammate off the field as he was on it — though actual production would be cause for argument about that.

It wasn’t long after Roger Lewis Jr. made his acrobatic 34-yard Beckham-esque catch in overtime that set the Giants up on the Kansas City 2-yard line for the game-winning field goal and a 12-9 victory that Beckham reached out to Lewis to congratulate him.

“I get a lot advice from Odell,’’ Lewis said Tuesday. “He’s not just a top receiver in the league, he’s a captain in our [receivers] room, he’s a leader in our room. So whenever I get to talk to 13, it’s a blessing.

“He’s like my brother. He reaches out to us almost every day. He makes sure we’re good mentally and spiritually. He’s a special guy, so when he reaches out, something good happens.’’

Some good things happened in Sunday’s upset win over the Chiefs with the backup receiving corps, which has been forced into duty since Beckham and Brandon Marshall were lost for the season in the same game.

For the first time since Beckham was lost, the young Giants receivers contributed not only with some semblance of consistency, but with a few game-changing big plays. It’s a trend the Giants hope continues when they play the Redskins on Thursday night in Maryland.

Lewis finished with three catches for 55 yards against the Chiefs, highlighted by that 34-yarder on fourth-and-5 in overtime that won the game. Tavarres King had three catches for 48 yards, and Travis Rudolph had three for 34 yards.

All three receivers credit Beckham’s behind-the-scenes leadership for boosting their confidence and empowering them to be better.

“It’s super powerful,’’ King said. “I’ve said before that ‘O’ is a powerful positive presence in this locker room, on the field and off the field. Having him here on our side is huge. He’s just a good leader, somebody you listen to, a student of the game.’’

Rudolph said Beckham “talks to us every day,’’ adding, “The main thing he tells me is to go out there and be me and don’t overthink it, that it’s still football. He said I have what it takes to play in this league and to play with confidence.’’

Asked what that meant to him, Rudolph said, “It’s cool. Would it be cool for you?’’

It’s been cool for Lewis, who spoke with reverence about what Beckham has done for him.

Asked what Beckham’s reaction was to his Beckham-like catch against the Chiefs, Lewis said, “He’s seen me do that before in practice. When that happened, it was just the world seeing it, not just teammates and coaches.’’

Beckham’s message to Lewis after the win over Kansas City?

“He told me, ‘Keep going. Don’t stop. You’ve always been able to do this, now it’s time to transition it into the games. Stay in it,’’’ Lewis said. “That’s huge. That’s like a brother of mine, and I can reach out to him any time. He never steers me in the wrong direction.’’

Without Beckham, the Giants are going to need more of the same things they got out of Lewis, King and Rudolph against Kansas City. The three, after all, have combined for 33 catches and three TDs while Beckham, who hasn’t played in the last five games, finished his season with 25 catches and three TDs.

“I thought Roger and TK both stepped up and made some nice catches, nice plays,’’ Eli Manning said. “They’re getting more confident. We’re getting on the same page with each other and knowing how guys are going to come out of their breaks and do certain things. Obviously, the more practice and more game experience, the better off we’ll be.’’

Lewis, sounding a bit like the uber-confident Beckham, said he feels like this is just a beginning.

“I feel like I’m getting into more of a rhythm, and now I’ve been able to showcase it in a game,’’ he said. “If I’m in a game and I catch a pass like [the 34-yarder against the Chiefs], it puts me in that mode like, ‘All right, it’s time to go.’ And once I get in that mode, I don’t think anybody can to stop it.’’

Bold words from Lewis.

Empowered by Beckham.