I hope Walker can come back in the spring and be reasonably effective. He was never great, but he was servable, especially if he is the fifth starter. For awhile in the past, the Phillies were very successful in games he started. This year has been a lost year for him. If he is truly healthy and can regain his composure next season, he could be of value.
There is also the possibility of a trade for another player with a similar contract who has fallen off in performance and favor with his team. The hope being that both would benefit with a new start with a different team.