PHILADELPHIA (973espn.com) - Mystery solved.

Because Tim Jernigan's recent back injury, which required surgery for a herniated disc, happened away from the team and the NovaCare Complex, a provision in the 2011 CBA would have allowed the Eagles to cut the veteran defensive tackle with no cap repercussions and void the $11 Million guarantee for his 2019 salary.

That's called leverage and its the reason Jernigan agreed to a reworked deal that will pay him $3 million in 2018 and takes all the guaranteed money off the table for the next three seasons.

In other words, it was better than nothing, from the player's perspective.

The timetable for Jernigan after he underwent the procedure last week is four to six months on the shelf, the former of which would have him ready to at least start practicing again near the start of the 2018 campaign while the latter would have him out until the middle of the season at the earliest.

Expect an expanded role for veteran free-agent acquisition Haloti Ngata next to Fletcher Cox on the interior of the Philadelphia defense in Jernigan's absence along with additional snaps inside for trade pickup Michael Bennett.

Younger players like Destiny Vaeao and Elijah Qualls will also try to catch Jim Schwartz's eye in offseason work.

-John McMullen covers the Eagles and the NFL for 973espn.com. You can reach him at jmcmullen44@gmail.com or on Twitter @JFMcMullen