I think Kofi must have been a casualty of the process. The Jazz signed and waived 3 Ex. 10 guys today (including Jackson), and they had already done 3 previously (Morsell, Williams, Bass), I think. So (following Ken Clayton, I think), they've reached their limit of 6 Ex. 10 signings.
Maybe with Potter as a 2-way, they figured they didn't need another center in Kofi on the Ex. 10?