Did any of the team members or the coaches complain? If not, there was no violation. The 1st amendment guarantees that government will not make a law "prohibiting the free exercise" of religion. If there was no coercion, there is no violation. If some leftists are butthurt that there are believers willing to proclaim and act on their beliefs, why, there's no right for them to not be outraged. They only make themselves look more and more like the vicious, intolerant harpies they really are.