Daniel Kelly will become the latest youth talent to leave Celtic for another team before a sustained first-team breakthrough. It was confirmed earlier this week that Kelly has signed a pre-contract with Millwall in the English Championship and will officially join up with them in January. There’s still a chance that the two clubs come to an agreement before the end of August to hasten his move south, but it’s reported that valuations and add-ons are too far apart at this stage. It’s been known for a while that Kelly had one foot out of the exit door after Brendan Rodgers revealed he was no lon…