The former first-round pick, who rushed for 1,200 yards and 14 touchdowns over his two seasons in Philadelphia, is still dealing with the lengthy rehabilitation that comes with having a herniated disc in one's neck.
"It's a neck injury and everyone is very careful that when, if he comes back to football, that he is 100 percent healthy and ready to go," Rapoport said. "With these neck injuries -- we saw with Koa Misi going on injured reserve, we've seen it with Zach Orr, who] has not yet signed with anyone [after announcing he's going to come back -- you have to be very cautious about some of these neck injuries.
Mathews' cap number is $5 million this season, though the team would save nearly all of that by releasing him. Despite averaging nearly five yards per carry over the last two years, the serious injury suffered by Mathews combined with his previous medical history may make him a roster casualty when all the smoke clears.