It is true that the world of sports can be a very godless place: but can't all aspects of life be like this? As I read the New Testament, I do not see Jesus avoiding "sinful" places. He went there, rather, to transform them.
If, as we have suggested, sports is part of God's creation and our ability to play and enjoy sports, a gift from God, then there is every reason for us to use those gifts for God's glory.
As an activity in which we can use the gifts and abilities God has give us, sports is as valuable and significant as any other aspect of life. Playing sports is as legitimate as any other human activity. It has been said: "How you handle fame, success and failure and your perspective on life, is what glorifies God, not the trophies and prizes and acclamation".
Are sports sinful? Not at all, but, sin sure makes itself available when we lose our perspective. Just like anything else in life we need discipline, self-control, and a right attitude to reap the benefits and grasp the life-lessons participating in sports has to offer us all.