SEATTLE -- X-rays were negative on the left knee of Lions tight end Eric Ebron after Detroit's 13-10 loss to the Seattle Seahawks on Monday night, according to a league source.

Ebron, who is expected to have an MRI on the knee, left the game and did not return after suffering the injury in the first half. He left the game with 22 yards on two receptions.

Lions coach Jim Caldwell did not have any additional updates on Ebron's status after the game.

Ebron initially had been listed as questionable to return as he went back to the locker room during the first half, but he did not return after being looked at by trainers with a little more than six minutes to play in the first half.

Lions coach Jim Caldwell had no postgame update on tight end Eric Ebron's knee injury, but a league source told ESPN's Adam Caplan that X-rays on the knee were negative and that Ebron is headed for an MRI. AP Photo/Scott Eklund

Ebron had turned into the No. 3 option for the Lions in the passing game with 13 receptions for 157 yards and two touchdowns entering Monday night.

His injury leaves Detroit with one healthy tight end, Tim Wright. Brandon Pettigrew has missed the past three weeks with a hamstring injury.

Caldwell said after the game that defensive tackle Tyrunn Walker's ankle injury, for which he was carted off the turf in the fourth quarter, "is significant. There's no question about that."

Caldwell had no further updates on defensive tackle Haloti Ngata (calf) or linebacker Travis Lewis (ankle), who also went down.

Ngata, who was acquired by the Lions in an offseason trade, missed much of the second half after hurting the calf. Lewis injured the ankle while covering a punt shortly before halftime and was helped off the field by trainers. He returned for one play in the second half but didn't leave the sideline thereafter.

Ngata said he thinks he is going to have an MRI on his injured calf Tuesday but that "I don't think I'm too worried, but we'll see what the pictures look like."

The Lions finished the game with two defensive tackles, Caraun Reid and Gabe Wright, after Walker and Ngata both left.

ESPN NFL Insider Adam Caplan contributed to this report.