Weaver, who hails from Solihull, has been at Blues since the age of 12.
After progressing through the age ranks, he has gone on to become a regular for the Under-23s.
The stopper was loaned out three times during the 2018/19 campaign.
The first of which was with Hungerford Town in the National League South, for whom he made 13 appearances.
He then had time out on loan at Kidderminster Harriers and Hednesford Town.
That was after beginning the season on the bench for Garry Monk's side in the Championship opener against Norwich City.
And Weaver ended the campaign again as back-up, among the substitutes for the final match at Reading.
In the summer of 2019 he signed a new one-year contract.