The person said Thursday the contract is pending a physical. The person requested anonymity because the deal has not been announced. Several media outlets earlier reported the deal.
Marcum went 7-4 with a 3.70 ERA for Milwaukee last season in 21 starts. He missed time with an elbow injury. He also missed the 2009 season after having elbow-reconstruction surgery while with Toronto. Marcum is 57-36 with a 3.76 ERA in seven seasons.
The Mets are the last team to agree to terms with a major league free agent.