Grace and the Spiritual Disciplines

What is the relationship between spiritual diciplines and grace? Does participation in the spiritual disciplines mean that we are not resting in God’s grace? Dallas Willard shares the analogy of a baseball player to describe how the disciplines enable us to grow in our discipleship:

We are saved by grace of course, and by it alone, and not because we deserve it. That is the basis of God’s acceptance of us. But grace does not mean that sufficient strength and insight will be automatically “infused” into our being in the moment of need…A baseball player who expects to excel in the game without adequate exercise of his body is no more ridiculous than the Christian who hopes to be able to act in the manner of Christ when put to the test without the appropriate exercise in godly living.