Could be a lot more to the thinking here than just his playing ability.
If Powell wants to make a point that non-committed players will be shown the door, perhaps he also wants to make a point that commitment to the cause will be rewarded.
Over the next 2.5 years he may be leaning on Ratchford to be a bridge between the coaching staff and players, and use his experience to help blood the younger players.
He may not be a starter anymore in our eyes but he still has plenty to offer.