Just to be clear its u21 he's playing at, usually we'll talk about u 18 as Youth.
He played alongside Conolly at Centre back two matches ago , against Chelsea, and they both got good reviews. Holgate may have been the third youngster in contention last Saturday, although more likely to have been Dowell. Anyway, it would seem Connoly has nudged ahead of him as Holgate remained with the U 21s last Monday.
Although he's got some good reviews ,he's made some highly visible mistakes at u 21 level , the most recent being a poorly hit back pass against Middlesborough which gifted them a goal. Youngsters will make mistakes, so shrug and move on but it can affect perception on when they are ready to be exposed to the first team. He's played his first games for England u 20s this season, appeared on the bench for the first team at least once but didn't get on , and has generally made good progress . There is a danger of him being compared with Stones and Galloway re our expectations of him but he's still only 19, plenty of time for him to be developed further.