ENGLEWOOD—Charlie Jo Derby was only on her third day on earth when she received evidence her father was a man.

A.J. Derby, Charlie’s dad, had nearly made a terrific play against the Los Angeles Chargers last Sunday at the temporary NFL stadium that was StubHub Center. He was running down the left sideline on the first possession of the game when quarterback Trevor Siemian made a scrambling, wild heave into traffic.

Derby rescued the throw by coming back to the ball, outmaneuvering two Charger defenders in the process, and making a big-time catch. Derby took off and was fighting for more than the 23-yard gain he already had when the ball was poked out from behind by safety Adrian Phillips.

The Chargers recovered the fumble. It was the first of three turnovers committed by the Broncos’ offense, which never did score in losing the game.

After the 21-0 loss was complete, the last thing he wanted to do was answer questions about his fumble, but this is when Charlie Jo’s dad manned up.

Anybody can talk about the good plays in a winning locker room. It takes a man to stand up and address a moment of failure. Derby did so, saying fumbling away a potential big play was “unacceptable.”

“Yeah, it’s part of the job,’’ Derby said last week in a sit-down interview with 9News. “Everyone is going to mess up at some point in their career. At the same time, you can’t let it ruin how you approach people and I try to be the best I can every day.’’

Derby missed the Broncos’ practice last Wednesday as his wife Callie went into labor. It was until 6:04 the next morning that 6-pound, 15-ounce Charlie Jo came into the world. Derby hung around with his wife and first child for a while, then made it to the Broncos’ practice that started around noon.

“The experience was great,’’ said Derby, led the Broncos last week with six catches for 66 yards. “Honestly, didn’t know what to expect. It was a lot longer than I thought it was going to be, the process. But had a healthy baby girl. Charlie Jo, Thursday morning and went to practice Thursday and went to the game.’’

Back to business for Derby includes again giving his good friend Siemian some help. After the Broncos scored just 10 points in a loss to the lowly New York Giants, and suffered the franchise’s first shutout in nearly 25 years last week against the Chargers, several local media outlets ran surveys asking, in so many words, if Siemian should remain the quarterback.

The timing of these surveys brought predictable results as they were all overwhelmingly in favor of replacing Siemian.

“I don’t agree,’’ Derby said. “I don’t read any of that stuff. This building believes in Trevor. This team does. We’re behind Trevor 100 percent. He’s a good quarterback. He’s a great quarterback and I think he’s got a lot of upside, we’re just going to have to give him time.’’

So why are the Broncos in such an offensive funk that actually covers four consecutive games of scoring less than 17 points?

“In a lot of ways, we have 10 out of 11 guys who are on the same page, and one is messing up,’’ Derby said. “Or we’re off 6 inches on a throw, or 6 inches on a run fit. We got to fix those little details and that’s what we’ve been grinding here this week and we’re putting in the extra time to make sure we can get that done on Monday night.’’

Derby was a quarterback for, first, his hometown Iowa Hawkeyes, then Arkansas, before he finally relented and agreed to the conversion to tight end for his senior season with the Razorbacks.

He did such a nice job, none other than Bill Belichick and the New England Patriots selected him in the sixth round of the 2015 draft. After spending his rookie year on injured reserve, Derby played in four games for the Patriots in 2016, then was traded at midseason to the Broncos.

“Honestly, I was pretty upset,’’ he said of the trade. “Not because I wasn’t happy to come to Denver. I was upset they thought I was tradable. In my mind, I took that as a competitive edge and every day I’m working to try to prove that they made a mistake and just try to do the best I can for the Broncos.’’

Derby is still learning his position, yet he is the Broncos’ fourth-leading receiver, and No. 1 among tight ends, with 15 catches for 190 yards and a touchdown through six games.

He’ll have a chance to pad those numbers Monday against the Kansas City Chiefs, who allowed Oakland tight end Jared Cook to rack up six catches for 107 yards last week.

“I think we have to take advantage of our opportunities,’’ he said. “Their offense is good. We believe our defense is going to get some stops but they’re a good offense, they’re going to put some points up so we’ve got to match that. We’ve got to put more up than they do.’’