Signing a player before his contract is actually up?
What a nice concept
2 things have to occur to give a player a 3rd contract.
1) Player is performing well still
2) Into the non guaranteed portion of the contract, thus higher base salaries, now that the SB has be used to average out the first 2 years of the contract's lower base salary. So, the team is able to drop the cap charge with a SB.