If you pick him up on waivers, you're responsible for the entire contract. He's not a freeagent until he clears waivers.
Assuming he clears waivers and becomes a free agent, any team that signs him is only responsible for the league minimum (327K per year for MLB contracts). If you're inseason now, the current year's salary is prorated.
The remainder of the contract is paid by the original team.
An example of such a player is:
Stu Boehringer