Lawrence's shoulder was always his trump card... He absolutely has to have the surgery, it was a matter of when, not if.
With that in mind, Tank flat out told Jerry that if he didn't get his deal - he would hold off until the season started to have it done.....thus missing most (or all) of the 2019 season. Which means he would have singed and rec'd his Franchise Tag money, all the while resting at home... It was genius on his part - and it worked.