This was likely:

Jernigan was set to hit the cap at $13 million this season, which was comprised of $11 million in base salary and a $2 million signing bonus. They’ll eat a total of $2 million dead cap this year while freeing up that $11 mill for use elsewhere.

Now Jernigan becomes a free agent, though he could of course sign a new deal with the Eagles. Timmy had offseason surgery after the Super Bowl win and only played five games this season. He made his debut in the week 12 New York game, then missed three in a row with back spasms before returning for the Houston game in week 16.

That 2018 surgery led to the re-negotiation of his original contract, which voided the money guaranteed for the rest of his deal.

Edit:

I had it wrong. It’s actually $7 million in cap savings and $6 million dead cap, because he had signing bonuses next year and the following year, also of $2 million: