During their 28-14 loss to the Tennessee Titans on Monday night, the Dallas Cowboys were dealt another blow with star linebacker Sean Lee suffering a hamstring injury.

The initial expectation was that it would keep him out of the lineup for a short period of time. However, David Moore of The Dallas Morning News is reporting that the timetable for his return is in the range of four to six weeks.

Lee injured his left hamstring in Monday night's loss to Tennessee and will miss the next four to six weeks, a source said. The front end of that time frame would put the linebacker back on the field for the Cowboys rematch with Philadelphia on Dec. 9. The tail end would put his return against Tampa Bay on Dec. 23 with two weeks left in the regular season.

This adds to what has already been a frustrating 2018 campaign for Lee, as he has missed three games due to a nagging hamstring issue that has also impacted his play. He currently has 27 total tackles, a fumble recovery, a half sack, and a pass deflection. This will once again leave him out of the mix for a lengthy period of time in what will be a decisive stretch of the season for Dallas.

When healthy, Lee has proven to be the anchor of the Cowboys' defense that has seen him record more than 100 tackles in each of the last three seasons. His absence now puts the bulk of the pressure on linebackers Jaylon Smith and Leighton Vander Esch to carry the load with that group of the defense. The two have played a huge part in helping Dallas put forth some improved play on that side of the ball. The team ranks third with 18.9 points allowed, third against the pass, and seventh against the rush.