It's another mailbag Friday and in this one John Karalis answers the question of whether the Celtics are really contenders, Plus, a creative, under-discussed use of the Hayward traded player exception, and who the starting lineup might be.Support Us By Supporting Our Sponsors! Built BarBuilt Bar is a protein bar that tastes like a candy bar. Go to builtbar.com and use promo code “LOCKEDON,” and you’ll get 20% off your next order.BuiltGoVisit BuiltGO.com and use promo code “LOCKED,” and you’ll get 20% off your next order.HeadspaceYou deserve to feel happier, and Headspace is meditation made simple. Go to Headspace.com/lockedonnba for a FREE ONE-MONTH TRIAL with access to Headspace’s full library of meditations for every situation. Learn more about your ad choices. Visit podcastchoices.com/adchoices