Jerod Mayo made his first mistake before the New England Patriots even played a snap against the Los Angeles Chargers on Saturday.

About 30 minutes before kickoff at Gillette Stadium, Mayo told the pregame radio show 98.5 The Sports Hub that Antonio Gibson would start at running back over Rhamondre Stevenson. The announcement wasn’t necessarily a surprise, as Mayo had hinted earlier in the week that Stevenson could be benched after he lost his seventh fumble of the season against the Buffalo Bills last Sunday.

However, when the game began, it was Stevenson in the backfield who made New England’s first offensive attack, and Gibson watched from the sideline as Stevenson scored a 5-yard gain on the Patriots’ first play from scrimmage.

The about-face puzzled NFL Network color analyst Ross Tucker, who suspected that Mayo had also told the broadcast team that Gibson would start in place of Stevenson. So why the sudden about-face?

Mayo didn’t give many answers after the game.

“That was just a coach’s decision,” the Patriots head coach told reporters in his postgame press conference. “Coach’s decision.”

Asked what led to Stevenson starting ahead of Gibson – and whether anything happened in the 30 minutes before kick-off that might have led to the substitution – Mayo was again tight-lipped.

“I understand the question,” Mayo replied. “Look, it’s a coach’s decision. That’s all I know about it.”

That’s a completely unsatisfactory explanation for a strange controversy caused entirely by Mayo. If the first-year head coach had simply said he would decide who would start at running back at kickoff — or simply not announced that Gibson would start — we wouldn’t be having this conversation. However, by saying one thing and doing another, Mayo makes himself and his coaching staff look dysfunctional.

And by declining to provide details after the game, he opens the door to all sorts of speculation about why Stevenson started in place of Gibson – an otherwise insignificant development that had no bearing on the Patriots’ lopsided 40-7 loss .

“It’s just an unforced error,” Patriots insider Tom E. Curran said of Mayo’s decision Patriots Postgame Live. “If you don’t start (Stevenson), or if you start him, the game doesn’t depend on that conversation. Everyone understands that the guy is going to play football that day. He is one of you who is better.” So when someone asks, “Who starts?” Say, “I haven’t decided yet.”

“You don’t have to make it a one-car accident, which is what he did by giving an answer he can’t stick to.”

Stevenson finished the game with one rushing yard on two carries – his only other run after his 5-yard gain was a 4-yard loss – while Gibson rushed for 63 yards on 12 attempts.