The 32-year-old had been unavailable for selection during the majority of this season, with academy keeper Matt Alexander stepping up to provide back-up to Remi Matthews.
It is understood that Keith Hill will look for senior cover as part of his recruitment plans next month if the right signing becomes available.
Alnwick was a big part of Wanderers’ promotion squad in 2016/17 and won player of the year 12 months later in helping to keep the Whites in the Championship.
Injuries and the arrival of Matthews meant he played just six times in 2019, however, and he has spent the majority of the last few months at home in the North East with his family.
Bolton, who have declined to go into greater detail on Alnwick’s departure, announced on Friday that the keeper was free to seek alternate employment elsewhere after two-and-a-half years at the Unibol, during which time he made 95 appearances.
“Everybody at Bolton Wanderers Football Club would like to thank Ben for his service and we wish him well with his future endeavours,” a statement read.
Hill says he will focus on the upcoming two home games before speaking with the four loan players – Josh Earl, Jake Wright, Thibaud Verlinden and Liam Bridcutt – to see if they want to extend their stay with Wanderers beyond January.
The Bolton boss is bound by the constraints of a transfer embargo, which means he may have to move some of his fringe players on before bringing new signings in.
For now, however, he wants to end the year on a winning note.
“At the moment I can afford to think about Shrewsbury and Burton, and then we have a gap where we don’t play for a week, a break-off point where I can talk to players and say ‘do you want to stay, or do you want to go?’ “We don’t want a total rebuild but we want to freshen things up and support the players who are here and fighting,” he said.