Chicago Bears head coach Matt Nagy addresses the media at Halas Hall in Lake Forest on Tuesday, Jan. 9, 2018.
Chicago Bears head coach Matt Nagy addresses the media at Halas Hall in Lake Forest on Tuesday, Jan. 9, 2018. — H. Rick Bamman -

LAKE FOREST, Ill. – The Great Play-Calling Mystery of 2018 has been solved.

Matt Nagy, who was introduced as the 16th head coach in Chicago Bears history on Tuesday, was on the Kansas City Chiefs’ sideline less than 48 hours before he was hired to his new post. And Nagy confirmed in his introductory press conference that it was he who was calling the offensive plays for the Chiefs as they watched a 21-3 third-quarter lead evaporate in a shocking 22-21 wild-card loss.

“Yeah, I called every single play in the second half,” Nagy said.

So there you have it.

Chiefs fans are understandably upset with where they are right now, and some of them might be happy the 39-year-old Nagy is gone given this new information. After all, in their eyes, we now know that this is the rotten scoundrel who failed to give Kareem Hunt more than five carries after the first quarter when the Chiefs were up 14-0. Among other heinous indiscretions.

There’s also another layer to this: Chiefs head coach Andy Reid semi-fell on the sword for Nagy, his former lieutenant, quipping after the game that he called all the good plays against the Titans and that Reid called all the bad ones. This is familiar ground for Reid, who has muddied the play-calling waters for years, in some cases.

Chiefs fans were nonplussed – by all of it. They previously had heard Reid say that now Philadelphia Eagles head coach Doug Pederson was the play caller during the 2015 season, even though some evidence suggested that Reid was heavily involved, if not the true conductor on game days.

The feeling was that Reid really wanted Pederson to get a head-coaching job to add branches to his tree that now includes Pederson, Todd Bowles (Jets), John Harbaugh (Ravens), Ron Rivera (Panthers), Sean McDermott (Bills) and Nagy. Was Reid just covering for Nagy and trying to shield him from blame?

Will the real play caller please stand up?

Nagy already did. He owned it in the news conference, a time that, yes, was a joyous occasion after a whirlwind few days of wrapping up the Chiefs’ season, interviewing with Bears GM Ryan Pace and then landing in Chicago. But Nagy also was willing to be humble and accountable, putting the blame on his own shoulders, in what was an impressive first showing.

Some Chiefs fans might be glad he’s gone, and some Bears fans might be wondering who the heck the team just hired. Outside of Kansas City, Nagy was a relative unknown to casual football observers before Reid gave him play-calling duties initially. Saturday's game might have been the first time many non-Chiefs fans watched them and had any clue who Nagy was. It wasn't a stunningly good showing on its own.

Now he’s the head coach of one of the most tradition-steeped teams in NFL lore.

Too much too soon?

No – and his straight-up ownership of the mistakes he made in that game seemed to be strong evidence that accountability will be one of his best characteristics. There’s a lot on Nagy’s plate as he navigates his first NFL head-coaching job, and he plans to call plays again this year.

But don’t take 30 minutes of poor judgment and play calling as a sign that Nagy is a bad coach. One game never should define any coach, especially one before Nagy gets his chance to run his own ship. Maybe he's still a little green. But Nagy also seems willing to learn what he doesn't know.

If Pace liked him before that game, he certainly shouldn’t have changed his mind after a few questionable decisions in that game. A general manager can hire all the fancy play callers they want … but if they don’t have someone who is willing to admit mistakes and learn from them, they won’t be hiring a leader.

“That there, that’s a learning situation for me,” Nagy said. “I’ve gone back and I’ve looked at [the game tape]. There were some scenarios where I wish I would have made some different choices with the play call.

“But you know, for me, that wasn’t a failure in my book. I’ll learn from it. I’ll grow from it. So I use that as a strength for me with the Chicago Bears.”

As well he should. Nagy had a lot of copilots in Kansas City and with the Philadelphia Eagles, where he got his NFL start under Reid in 2008. But now Nagy is flying solo – and he just aced his simulator test in front of the media by saying the failure in that loss was on him.

We suspect he said something similarly direct to Pace, who watched the game at The Raphael Hotel in downtown Kansas City on Saturday and then met with Pace for more than four hours there the following morning. Pace, who admitted he had “mixed emotions” watching the game, came away from the interviewing believing in what Nagy was selling.

"There’s a lot of guys that can win an interview or win a press conference, you know?” Pace said. “But you’ve got to look for the substance behind it all. And Matt has a ton of substance."

Nagy of course was asked about how the quarterback-relationship dynamic works, which is a subtle media trick for asking: “How are you going to make Mitch Trubisky really, really great?”

But in that answer, Nagy laid out the three elements he thought were most important – trust, honesty and communication. To the last part, Nagy said: “When you fail to communicate, there’s gray area. When there’s gray area, bad things happen.”

Hearing that, and knowing that Nagy isn’t afraid to own up to his own shortcomings, Trubisky and his new head coach should be on the same page, which is a very good thing. There will be hardships and setbacks along the way – and yes, you hope Nagy isn’t having to apologize to his team or the media on a weekly basis for his mistakes.

But those growing pains are natural for any first-time head coach, especially one who will have a lot on his mind when the offense has the ball. Nagy made it clear, though, that everyone will be held accountable, no one more than himself, and that should be an excellent situation in which Trubisky can grow.

As he turned the page from Kansas City to Chicago, Nagy once more explained how mishandling some play calls – his calls and his alone – is actually a really good thing as he learns on the fly to be a head coach.

“You put in a lot of work and … going back to losing a player like [Travis] Kelce, you got to adapt,” he said. “I know that our offense and offensive staff supported me …

“But I called every play in that second half. I stand by it. I promise you I will learn from it.”