Sunderland might have missed out on Lyle Taylor to League One rivals Charlton Athletic, but the Wearsiders are at least feeling good about landing another of their transfer targets.
The 24-year-old made 43 appearances as he captained Posh during the 2017/18 campaign, keeping eight clean sheets as the London Road side finished ninth in League One.
Baldwin’s experience of third tier football could make him a valuable addition to Sunderland, while it is understood that he could be available for as little as £250,000.
It is understood that a number of clubs are interested in the Barking-born centre-back but Sunderland are confident of striking a deal. Baldwin has already played in the north east during his career, spending three years at Hartlepool United between 2011 and 2014.
Baldwin would be the second new centre-back to arrive at the Stadium of Light this summer, following in the footsteps of former Turkey U21 international Alim Ozturk.
The 25-year-old signed a two-year deal after leaving Turkish second tier side Boluspor.