As a Christian, I would take extreme issue with any player expressing a belief that their personal faith resulted in them being "favored" by God over other players on the field, and I don't see how any thinking and knowledgeable person could do so.
Thanking God and expressing gratitude for being blessed in your endeavors is not narcissism on the part of a believer; it is acknowledging that every day and every moment is a gift from God to each of us, regardless of what we believe. God doesn't love me any more than he loves BKB, or any person on here who claims to be agnostic, atheist, wiccan, muslim and so on. What a Christian is doing in that circumstance is expressing that love back...thank you for this moment, this feeling, thank you for the success to which I wasn't entitled and which I didn't earn on my own. Ironically, it is humility, not hubris. We are not claiming that God cares about an incomplete pass, or that he cares more about us than someone who doesn't own a stack of Christian music CDs -- we are claiming that whatever we have been given, blessed with or achieved comes from God and not from us.
What it is normally not is proselytizing, at least in the sense that the poster describing it as being marketing, like Proctor and Gamble. I don't believe that I can "convince" anyone to come to faith in God; I can simply express what my faith means to me, live it out as best as I can, and hope to be an example to other people, which is what many of these players do. I believe that coming to the same faith will be a blessing and a benefit to someone's life, but that it is also something that they must work out on their own, directly with God.
Many times, those open expressions of faith are meant for other Christians, helping to build, affirm and encourage them. When a young kid in school is being picked on for his faith, which does happen, and he sees a guy like Warner or Tebow or McCoy speaking out and expressing his, he no longer feels like he's taking on the world by himself.
No person can truly judge or see the state of another person's heart, but there are a lot of players who I've seen over the years who I believe are completely genuine Christians, whose faith is essential to who they are and not a show for the cameras. Colt McCoy strikes me that way, as does Tim Tebow. I've personally met Jim Lauranitis at church and found him to be a remarkably humble, decent and genuine person. Regardless of what one's beliefs are, I think that he's an excellent role model and example of how to life. It just so happens that for him, his faith guides and directs that.
So, rest assured, devout atheists, Tim Tebow is not trying to force his faith down your throat by using tiny adhesive patches on his face.
Also, ORD, keep in mind that a university being public does not require that all of the students at that university adhere to "secularism" any more than a Catholic university requires all of it's students to be Catholic. No student surrenders his first amendment rights at the university gates, and in fact, a robust discussion about faith, religion and philosophy is directly in keeping with the mission of a university, whether private or public. What the University of Florida cannot do is sanction one faith over another or over none at all. That certainly doesn't prohibit any individual student or employee from doing so themselves. Prohibiting the establishment of a state religion does NOT prohibit public expressions of religions or faiths. In fact, during one's time at a state university (and even many "religious" ones), a student will encounter many, many more arguments for atheism, secularism, agnosticism and humanism than they will for any creative deity or monotheistic religion. The existence of Tim Tebow hardly turns Florida or any other state run institution into a virtual seminary.
Since the question will be asked (and has been), "What if a player wore Koran verses?" He might not be popular with some fans, but I doubt that the media would criticize it, and I personally would not care or mind. Outside of posting on Buckeye Planet, I participate in amateur sports car racing, and one of our rival teams is run by a friend of mine who is a Pakistani muslim. His cars carry huge, and I mean HUGE Islamic crescents on them (representing the Pakistani flag) and to my knowledge, he has never received one negative comment about it. Those symbols don't represent my faith, but for him they represent his faith and cultural heritage and as far as I am concerned, he is completely free to use them as he wishes. The same would go for a player who wants to write NO and GOD on his eye blacks. If that's what you believe, express that. It may anger some people and that's the risk you take, but obviously guys like Tebow and Warner are angering some people. No one is going to like everything you believe, even if not everyone kills people (or dogs).