The goalkeeper joined the Academy last year after impressing on several occasions against the Reds for his former team Blackburn Rovers.
The 18-year-old – who turns 19 next week – started last season in the U18s but was turning out for the U23s by September.
Winterbottom's debut in Premier League 2 was a memorable one, making a spectacular penalty save against Derby County.
He was also part of the U19 team which secured top spot in their UEFA Youth League group and the U21 team that took on Football League opposition in the group stages of the Leasing.