Goalkeeper Liam Roberts has signed for Championship side Middlesbrough.
Roberts enjoyed a successful season with the Cobblers and Northampton Town manager Jon Brady says the club and player have parted on excellent terms.
"Liam was good for us and we were good for Liam," he said.
"We identified Liam when he was available last summer as part of our thorough recruitment process and not only did he do very well for us, we worked with Liam to not just help and improve his overall game but to get his career moving in an upward direction again.
"We were keen to try and keep hold of Liam and we made several good contract offers but in the end the chance to move to the Championship and a club like Middlesbrough was an excellent opportunity for him and I think everyone understands that.
"We thank Liam for his efforts and wish him well for the future. This was not unexpected and we are progressing our work to recruit a goalkeeper."