No. If he is picked up off of waivers or via trade, the new team picks up all the terms of the contract, including the vesting clauses (which is why he won't be). If he signs with a new team, it is a new contract.
The Red Sox must honor the terms of his Red Sox contract (i.e., they have to pay him the balance of this year's salary). But those terms require 497 PAs for the option to vest, which he didn't and won't get under his Red Sox contract. Any PAs from here forward would be under his new contract; they are not additive.