Callum and Tyler sign development contract deals.
The pair follow Marley Andrews in signing their first senior deals with the U's, as the club continue to shape their U21s squad for the next season.
Both players were a key part of last season's U18s league and cup double and have featured for the U21s in 2014/15.
18-year-old Tyler has shown his versatility over the last couple of years, not only featuring as a wide man but also at full back.
Combative midfielder Callum has taken the captain's armband for the U18s during this season. The 17-year-old will hope to follow in Sammie Szmodics and Tom Lapslie's footsteps in breaking into the first team in 2015/16.
The deals will be completed subject to paperwork clearance by the relevant authorities, and we will have reaction from the pair in the coming days.