That's a stretch. The reporter makes the claim. The quotes do not.
Wasn't my story, but there are others that say the same thing. (I can't find any with direct quotes, but stories like the following come from people covering the team.)
Cowboys owner and general manager Jerry Jones recently expressed hope that Dallas could retain McClain and plug him in at middle linebacker--his position in 2014, when he finished second on the team in tackles--while Lee moves from the middle to the weak side. Head coach Jason Garrett has said weakside linebacker is Lee’s natural position, and believes the move could help keep him healthy.
There were several factors in Lee moving to the weak side. Health was one of them because he would be better protected from blockers, not having to take them on as much, and better able to flow to the ball instead of having to fill the hole as much. Having McClain also played a role because McClain is truly a middle linebacker, which allowed Dallas to move Lee to a spot that better suits his abilities.
Not having McClain might change that, but the fact that Lee was able to stay mostly healthy last year might also convince the front office that the team is better off leaving Lee at WLB. Lee and Durant both have some flexibility, though, so it might come down to what's the better fit for the corps. I like Lee as a MLB so I have no problem with Dallas moving him bakc there,