Is it safe to play football with spondy?

Do you mean?: Do you mean "spondylosis" or "spondylolithesis"? The most severe complication from spondylosis that i can think of would occur in the cervical spine and cause reduction in flow of the vertebrobasilar artery (due to arthritic processes) which feeds the brainstem. Of course, injuries and prolonged pain are likely more easily acquired playing in people who have spondylosis and play contact sports.