 John will leave the Blues at the end of the season |
Cardiff Blues coach Dai Young says he is "extremely disappointed" to be losing his right-hand man Geraint John. John has accepted a job to run the youth academy of Gloucester's Hartpury College, but will stay with the Blues until the end of the season.
Young told BBC Sport: "He's been a huge help to me and I'll miss his support.
"He's been headhunted for the job. Everyone knows the qualities he's got. It's an opportunity he felt he couldn't turn down. I support him on that."
John has worked as Young's assistant at the Arms Park for the past three years, and helped develop Cardiff youngsters such as Jamie and Nicky Robinson, Rhys Williams and Ryan Powell.
Hartpury College has developed many young players for the professional ranks at Zurich Premiership side Gloucester.
The Blues are expecting to add Rob Howley and Neil Jenkins to their coaching staff, but Young says no decision has yet been taken on whether John will be directly replaced.
He said: "We haven't talked about that to any great length. Rob and Neil were coming in to complement Geraint so it's a bit of a blow to lose him."