Another ugly Sunday turned into another bloody Monday in the NFL in Week 4, and once again, some teams are scrambling to fill some big holes.

And for the third time already, the most painful news comes from Dallas.

Already without star receiver Dez Bryant (broken foot in Week 1) and starting quarterback Tony Romo (broken clavicle, Week 2), the Cowboys on Sunday night lost third-down running back Lance Dunbar to a knee injury. But unlike Bryant and Romo, it appears the Cowboys won't be getting Dunbar back any time this season.

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According to NFL.com, Dunbar will miss the remainder of the season with a torn ACL and MCL in his left knee. Dunbar suffered the injury while being tackled returning the second-half kickoff at New Orleans.

"He does a lot out of the backfield for us," current Cowboys starting quarterback Brandon Weeden told ESPN.com of Dunbar. "Obviously we saw that last week [against Atlanta]. And he ran the ball with a couple of big runs. He's electric."

Dunbar, 25, has been key for the Cowboys as they rely on a multitude of backs to take on the load previously shouldered by the departed DeMarco Murray. In that Week 3 game, Dunbar had 100 yards receiving on 10 catches. On Sunday, Dunbar had 54 yards rushing on only three carries.

It appears Christine Michael, acquired in a trade with the Seahawks last month, may be called on to take more carries behind starter Joseph Randle.

In Indianapolis, the news sounds a little better for quarterback Andrew Luck. After Luck missed a game for the first time in his career on Sunday, the Colts star was at practice on Monday, albeit in a limited role.

According to The Associated Press, Luck threw two short passes to running backs while reporters were present.

"He looked good," Colts head coach Chuck Pagano told reporters after Monday's walkthrough without helmets or pads. "He's moving in the right direction, trending in the right direction so he's a lot better than he was Saturday. He had a good day."

The bad news is the timing for the Colts -- they play at Houston on Thursday night, giving Luck limited time to recover. If Luck is unable to go, veteran Matt Hasselbeck will again get the start. He was 30 of 47 for 282 yards and a touchdown in Sunday's 16-13 overtime win against Jacksonville.

The Rams lost do-everything linebacker Alec Ogletree to a broken leg in Sunday's win at Arizona, and head coach Jeff Fisher told reporters on Monday that the third-year pro will undergo surgery on Tuesday.

Fisher added that Ogletree attended team meetings on Monday and was hopeful he could be placed on the injured reserve/designated for return list, which would allow him to potentially return to the field after eight weeks.

But if things do not go as the Rams hope, their leading tackler could be lost for the season.

Also around the league:

● Redskins tight end Jordan Reed is dealing with a variety of ailments, head coach Jay Gruden telling reporters on Monday that Reed is in the concussion protocol and also has a sprained MCL. Reed missed the final six games of 2013 after suffering two concussions that season.

● The Lions lost tight end Eric Ebron (knee) and defensive tackles Haloti Ngata (calf) and Tyrunn Walker (ankle) in Monday night's game in Seattle. None of the players returned to the game.

● The Seahawks also felt the pain of Monday's wild 13-10 win, losing running back Fred Jackson to an ankle injury in the first half. While X-rays were reportedly negative, an MRI exam is expected to be done. The Seahawks were already without All-Pro running back Marshawn Lynch, who missed the game with a hamstring injury.

● Broncos coach Gary Kubiak indicated star receiver Demaryius Thomas avoided any serious injury and is just a little sore. Thomas injured his neck in Sunday's win over the Broncos.

● Panthers linebacker Luke Kuechly is still in the concussion protocol, but he is reportedly hopeful to be back on the field for the Panthers' next game, in Week 6 against Seattle on Oct. 18. Kuechly has not played since suffering the concussion in Week 1 against Tampa Bay; the Panthers are on a bye this week.

● Giants tight end Daniel Fells underwent multiple surgeries for a staph infection in his foot and will miss the remainder of the season, NJ.com reported.