Do you consider yoga as a religious practice?

Recently, in his blog, www.albertmohler.com, Albert Mohler, head of the Southern Baptist Theological Seminary, examines the idea that the practice of yoga may be in conflict with the values of Christianity. Mohler’s argument is, in part, Christians are not called to empty the mind or to see the human body as a means of connecting to and coming to know the divine. Believers are called to meditate upon the Word of God — an external Word that comes to us by divine revelation — not to meditate by means of incomprehensible syllables.

I personally have regarded yoga as a stretching/centering/relaxation activity. Do you regard yoga as a religious practice, or as something else?