The 27-year-old started every league game in a stellar debut campaign at Sixfields, keeping 21 clean sheets and producing a raft of impressive performances between the sticks.
However, he would only agree a one-year deal when joining the club from Walsall last summer and is now out of contract. He has been offered the chance to stay but looks set to jump up two divisions and sign a two-year deal at Championship outfit Middlesbrough, with a medical scheduled for Monday.
Roberts is expected to be the back-up goalkeeper at the Riverside Stadium next season, with Boro also reportedly interested in signing Newcastle’s Karl Darlow and Leicester City’s Daniel Iversen.
Cobblers are in talks with a replacement but nothing is thought to be imminent on that front.