FRISCO, Texas -- Dallas Cowboys linebacker Leighton Vander Esch could miss four to six weeks because of a neck strain suffered in Sunday's loss to the San Francisco 49ers, according to multiple sources.

Coach Mike McCarthy said Vander Esch is likely headed to injured reserve, which means he would miss at least the next four games. After next week's game against the Los Angeles Chargers, the Cowboys have their bye, which could put Vander Esch's return at Nov. 19 at the Carolina Panthers or as late as Nov. 30 against the Seattle Seahawks.

He has a history of neck issues, missing seven games in 2019 and undergoing surgery after the season. He missed the final three games of last season with a neck injury. He suffered this injury with 13:59 left in the fourth quarter when he was pushed from behind and collided with Micah Parsons' leg.

X-rays taken at the stadium were negative, and Vander Esch had an MRI and other tests performed Monday.

"High caution is in place here," McCarthy said.

The Cowboys entered the season inexperienced and thin at linebacker. Rookie DeMarvion Overshown suffered a torn ACL in the preseason, which moved Markquese Bell from safety to linebacker. Second-year linebacker Damone Clark is playing through a shoulder injury. In the past two games, the Cowboys elevated linebacker Malik Jefferson from the practice squad, and last week they added Mikel Jones to the practice squad, but both were mostly special teams roles.

McCarthy said the Cowboys are exploring the possibility of adding a veteran.

"In our personnel meeting we touched on some potential opportunities," McCarthy said, "but we just want to make sure we have all of the information before we head down that road."

Because defensive coordinator Dan Quinn interchanges linebackers and safeties, they can make up for some of the loss. Safeties Jayron Kearse and Malik Hooker each can take over as the defensive playcaller in Vander Esch's absence. The Cowboys lost cornerback Trevon Diggs for the season to a torn ACL in a practice after two games.

"We also know there's going to be parts that challenge us through the year," Quinn said. "That's not just on our team, that's on every team. So that's why you better have a big, deep crew that can roll and be able to make adjustments."

One option could be moving Parsons to an off-the-ball linebacker role after he has played mostly as an edge player the past two seasons; however, taking Parsons out of a pass-rushing role would hurt the defense.

"That's part of the balance we'll have to face," Quinn said, "and work through it."

On special teams, the Cowboys will be without their best player in C.J. Goodwin, who suffered a torn left pectoral against the 49ers and will go on injured reserve. Pro Bowl returner KaVontae Turpin is working through an ankle issue, but McCarthy was not ready to rule him out of the Chargers game just yet. If he can't play, then Rico Dowdle and Deuce Vaughn would handle the return duties.

"With C.J., I can't describe how big of a loss that is on the game field, of course," special teams coordinator John Fassel said. "But, gosh, everything else he does Monday through Saturday, meeting room, practice field, mentorship. And he'll still do that, but we'll miss him on Sunday. That's a hard one to say, 'OK, you do this job,' because he's just different. He's very special."