This is not ideal.

The Giants were installed as 16-point underdogs going into Gillette Stadium for Thursday night’s game with the unbeaten Patriots, a betting line established before word came down that rookie quarterback Daniel Jones goes into the game against the NFL’s best defense without his top wide receiver.

It is more bad news for the Giants, as they will be without Sterling Shepard for the foreseeable future.

Shepard is in the concussion protocol once again, and a second concussion in four weeks means the Giants will monitor Shepard closely and he will not allowed to return to the field for quite some time. Shepard missed the second game of the season, against the Bills, after sustaining a concussion in the opener at Dallas.

The Giants are also likely to again be without star running back Saquon Barkley, dealing with a high ankle sprain, and suddenly tight end Evan Engram has a knee issue coming out of the 28-10 loss to the Vikings. With only four days before the Giants take the field again, the significance of any lingering physical ailment is heightened.

“It’s something you have to deal with,’’ coach Pat Shurmur said. “Every team has to deal with one of these short weeks.’’

Shepard played 56 of the 69 offensive snaps against the Vikings. He arrived at the team facility Monday morning and displayed symptoms to the Giants’ medical staff. That landed him back in the protocol and the frequency of these concussions is troubling.

“We’ll try to get him back,’’ Shurmur said. “He’ll be back on the field when they say it’s time.’’

With 4:04 remaining in the third quarter, Shepard was landed on by cornerback Xavier Rhodes as both players tangled going after a deep pass from Jones. Rhodes fell on Shepard’s head, twisting his helmet on the turf. Shepard looked shaken and he came off the field and was checked out before being allowed to return. He caught an 18-yard pass early in the fourth quarter.

The Giants were criticized for how they handled Shepard in the opening game, as he was given the go-ahead to return to the game even though he showed signs of being in distress.

The Giants last week welcomed back Golden Tate after he served a four-game suspension for violating the league’s policy on performance-enhancing substances. Tate played 46 snaps in his Giants debut, caught three passes for 13 yards and afterward said he hoped his role will increase. Now, it will, by default, without Shepard. Rookie receiver Darius Slayton caught a 35-yard touchdown pass against the Vikings and he and veteran Cody Latimer will be given increased work.

“He’s obviously a key piece to what we do and he’s been a big-time playmaker for us until this point,’’ Jones said. “We’re confident in the guys we got. We got guys who are ready to go and ready to make plays. We’re confident and I know those guys will be ready.’’

Shepard has 25 receptions for 267 yards and one touchdown. This leaves the Giants with only four healthy receivers. Two players they cut, Bennie Fowler and TJ Jones, remain available, but there is not much time this week to get them back on the roster in time to face the Patriots.

“It’s tough because you know how important this game is to [Shepard] and how much he wants to be out there,’’ Tate said. “Just hope he’s back soon, obviously over the last five weeks he’s been a huge part of our offense and been a big reason why we won a couple of these games. We want him back and healthy as soon as possible.’’

Tate’s role now gets magnified. He said after the loss to the Vikings he hoped his role would increase and clarified a day later he was not complaining.

“Were [my comments] taken at any point that I was unhappy?’’ Tate said. “Only thing I was saying is I hope I’m more involved at some point, but I do understand this is my first week back. There’s a process to this. When you throw someone right in the fire things can happen another way. I’m very happy to be a New York Giant. I think it would be more alarming if I said ‘No, I don’t want to play more, I don’t want more passes.’ I would look at that guy a little funny.’’

Now Tate will get more passes. The alternatives are dwindling.