Jaxson Dart suffered a knee injury when he was hit by two Rams defenders on the opening drive of the Giants' 28-6 loss on Monday night at SoFi Stadium.
The second-year quarterback was originally listed as questionable to return and then ruled out at halftime.
Dart will undergo an MRI on Tuesday after the team returns from the West Coast trip.
"We'll know more tomorrow," John Harbaugh said in his postgame press conference.
The initial belief is Dart avoided the worst-case scenario, which offered a sense of relief for the head coach and the rest of the Giants.
"There's no question," Harbaugh said. "The fact that it's not that outcome that you're talking about, the devastating outcome, is really good news."
The Giants (1-1) will have a short week to prepare for a Sunday 1 p.m. game against the Tennessee Titans (0-2) at MetLife Stadium. Any quarterback decision won't be made until the team has all the information.
Meanwhile, Dart isn't the only Giants player who flew home with an injury.
Outside linebacker Brian Burns suffered a low ankle sprain, according to Harbaugh, and left tackle Andrew Thomas (groin) did not finish the game. Additionally, Malik Nabers injured his shoulder, but the wide receiver was able to return in the first half.
"This is what it is," Harbaugh said. "All around the league, everybody deals with it. This is football. This is the NFL. This is what you do. Our task is not to lament it. Our job is for those guys to do everything they can to get back when they're ready. Just like Tae (cornerback Deonte Banks, who did not play due to a calf injury) will get back as soon as he can. Then go out and play the best football game we can with our football team and endeavor to win the football game. That's what we have to do so that's really the answer to the question. That's what we do. Those guys will be back. They may be back this week. They may be back next week. When they're back, that'll be great."
In last week's 28-20 win over the Cowboys, Dart became the first quarterback in NFL history to open a season with at least three passing touchdowns, 50 rushing yards, and a passer rating of 130.
On Monday, he completed three of five passes for 20 yards before suffering the injury on the seventh play from scrimmage.
Veteran backup Jameis Winston played the rest of the way, completing 11 of 27 passes for 111 yards and an interception while being sacked twice. Overall, the Rams recorded eight quarterback hits and 10 passes defensed.
The Giants have a third quarterback, third-year pro Jake Haener, on the practice squad.
"We're a resilient team," Winston said. "We know that those three (injured) guys specifically are some of the toughest guys that we have on our team. We're looking forward to seeing them rehab and fight their best to be available, and they will do that. We're just going to keep them lifted up in our prayers. We know that they fight. They fight to the end. That's just a part of this game that happens so they're also going to do the same thing to get back as healthy as they can be for our team."
Photos from the Week 2 matchup between the Giants and Rams on Monday Night Football
OLB Abdul Carter (3)
OLB Abdul Carter (3)
K Dominic Zvada (34), P Jordan Stout (15)
QB Jameis Winston (19)
P Jordan Stout (15)
LB Arvell Reese (52)
LS Ben Mann (58)
QB Jameis Winston (19)
P Jordan Stout (15)
OLB Brian Burns (0)
LB Tremaine Edmunds (49)
LB Arvell Reese (52)
OLB Abdul Carter (3)
CB Colton Hood (12)
TE Chris Manhertz (85)
LB Arvell Reese (52)
T Jermaine Eluemunor (72), OL Francis "SiSi" Mauigoa (65)
OLB Brian Burns (0)
RB Cam Skattebo (44), T Jermaine Eluemunor (72)
WR Malik Nabers (1)
CB Colton Hood (12)
OLB Kayvon Thibodeaux (5)
DL DJ Reader (98)
OLB Abdul Carter (3)
OLB Brian Burns (0)
DL Shelby Harris (93), OLB Abdul Carter (3)
DL DJ Reader (98)
LB Arvell Reese (52)
OLB Abdul Carter (3)
S Tyler Nubin (27)
OLB Abdul Carter (3), OLB Brian Burns (0) , DT Josh Tupou (94), DL Chauncey Golston (57)
LB Arvell Reese (52)
OLB Abdul Carter (3)
LB Arvell Reese (52)
RB Devin Singletary (26), TE Isaiah Likely (9), OL Francis "SiSi" Mauigoa (65), C John Michael Schmitz Jr. (61), T Jermaine Eluemunor (72)
CB Dru Phillips (22)
LB Arvell Reese (52)
DL Chauncey Golston (57), OLB Abdul Carter (3), DL Shelby Harris (93), DL DJ Reader (98)
S Jevón Holland (8)
OLB Abdul Carter (3)
LB Arvell Reese (52)
CB Colton Hood (12)
LB Tremaine Edmunds (49)
P Jordan Stout (15)
OLB Abdul Carter (3), DT Josh Tupou (94), LB Tremaine Edmunds (49), DL C.J. Okoye (99), CB Greg Newsome II (20)
LS Ben Mann (58)
S JT Woods (35)
DL Chauncey Golston (57)
CB Colton Hood (12)
S Jevón Holland (8)
CB Colton Hood (12), S Jevón Holland (8)
LB Tremaine Edmunds (49)
QB Jameis Winston (19)
QB Jameis Winston (19)
CB Colton Hood (12), S Jevón Holland (8)
OLB Zaire Barnes (46)
QB Jameis Winston (19)
OLB Brian Burns (0)
CB Colton Hood (12), S Jevón Holland (8)
DB Elijah Campbell (28)
OLB Abdul Carter (3), LB Tremaine Edmunds (49), DL C.J. Okoye (99), DT Josh Tupou (94), CB Greg Newsome II (20), LB Arvell Reese (52)
P Jordan Stout (15)
DB Elijah Campbell (28)
OLB Abdul Carter (3)
CB Dru Phillips (22)
K Dominic Zvada (34), P Jordan Stout (15), OL Marcus Mbow (71)
OLB Abdul Carter (3), DL C.J. Okoye (99), CB Greg Newsome II (20)
OLB Brian Burns (0)
S Jevón Holland (8)
OLB Zaire Barnes (46), WR Malachi Fields (88)
OLB Abdul Carter (3)
CB Greg Newsome II (20), S Jevón Holland (8), OLB Abdul Carter (3)
QB Jameis Winston (19)
CB Colton Hood (12)
LB Arvell Reese (52)
OLB Abdul Carter (3)
OLB Zaire Barnes (46)
DL DJ Reader (98)
LB Jack Kelly (51)
DB Elijah Campbell (28), RB Tyrone Tracy Jr. (29), LB Jack Kelly (51)
OLB Abdul Carter (3)
OLB Abdul Carter (3)
CB Greg Newsome II (20), S Jevón Holland (8), OLB Abdul Carter (3)
OLB Abdul Carter (3), CB Greg Newsome II (20)
S Jevón Holland (8), CB Greg Newsome II (20)
S Tyler Nubin (27)
OLB Brian Burns (0) , DL Chauncey Golston (57), DL DJ Reader (98), DL Shelby Harris (93), OLB Abdul Carter (3)
OLB Abdul Carter (3)
DT Josh Tupou (94), DL C.J. Okoye (99), LB Tremaine Edmunds (49), OLB Brian Burns (0) , S Jevón Holland (8)
OLB Abdul Carter (3)
LB Tremaine Edmunds (49), CB Dru Phillips (22)
DL Shelby Harris (93)
DL DJ Reader (98)
DL DJ Reader (98)
DL DJ Reader (98)
OLB Zaire Barnes (46), LB Jack Kelly (51)
