CHARLOTTE, N.C. — Carolina Panthers coach Matt Rhule is playing his cards close to the vest, but let me spell out exactly what I’m seeing at the team’s training camp in Spartanburg, S.C.: There’s no doubt Baker Mayfield is winning this quarterback competition. Mayfield hasn’t looked great by any means, but he’s been good enough to be better than Sam Darnold. Rhule said Saturday that he probably wouldn’t announce the winner of the QB competition until sometime after the New England preseason game Aug. 19. But it looks to me like Mayfield has taken the lead and now just needs to not mess it up a…
