NASHVILLE, Tenn. — The Zach Mettenberger Experiment is under way with the Tennessee Titans, and the first outing was encouraging, though it was a far cry from being declared a success.

Mettenberger’s final numbers looked good if you started him in fantasy football Sunday — 27 of 41 for 299 yards with two touchdown passes and one interception against the Houston Texans.

However, there is still much to work on, and even Mettenberger knows that. The Titans were behind 27-3 before Mettenberger directed two touchdown drives in garbage time. Tennessee lost 30-16 in a game that wasn’t that close.

It means that some of his completions came while the Texans were playing in soft zone coverage not to give up anything deep. Nonetheless, the Titans are keeping a positive outlook regarding Mettenberger and his development. Coach Ken Whisenhunt likes the way the sixth-round rookie stayed in the pocket and made throws, even with the likes of Texans defensive end J.J. Watt bearing down on him in the pass rush.

“One of the things I really like about Zach was this was a good defensive front,” Whisenhunt said. “They’ve been able to generate some pressure. He stood in there and didn’t seem bothered by it and made some good throws.”

As for his self-assessment, Mettenberger said he knows there is a lot to work on and a lot more responsibility now that he is the starter.

“This is my first game starting, and there’s a lot of things I could improve upon and I am going to improve on, but we’ve just got to keep working,” Mettenberger said. “Me being a spark is not just about me. There’s 10 other guys on that field that have got to help me along.

“Obviously, I can’t make a lot of plays on my own running around. Those other 10 guys, protecting, catching balls, catching tough passes for me is really going to help our offense get better.”

With the bye week upcoming, Mettenberger will get plenty of work on things that couldn’t be crammed into one week’s preparation as the starter.

“We want to get Zach as many reps as we possibly can,” Whisenhunt said. “I think in a competitive situation, which this will be, especially (Tuesday) and Wednesday, those will be good reps.”

Mettenberger’s debut as a starter was somewhat overshadowed by what transpired before and after the game. Mettenberger tweeted out a “selfie” photo of being clean-shaven from inside the locker room less than two hours before kickoff against the Texans.

It probably wouldn’t have gone any further than that had Watt not sacked Mettenberger and then made a “selfie” pose following the takedown. Watt was asked after the game about the celebration and took a shot at the rookie quarterback’s antics.

“It was one of those things where their quarterback had posted a few ‘selfies’ this week, including one before the game,” Watt said. “It is kind of a reminder that this is the National Football League, not high school. Welcome to the show.”

Watt was asked if Mettenberger’s actions offended him.

“I take my job very seriously,” Watt said. “If I was a rookie quarterback being named the starter for the first time in the league, I feel like I would be a little more focused than that. Maybe he will learn from it, maybe not. We won the game, so that is all that matters.”

But wait, there is more.

Whisenhunt revealed Monday that his rookie quarterback was encouraged to trim his hair and shave his beard after he was named the team’s starting quarterback. Mettenberger discarded the beard before meeting with the media Thursday when he was officially named the starter, and by Sunday he traded his Beatle-looking mop-top haircut for a more conservative look.

“I would not say that was a decision he made on his own,” Whisenhunt said of the quarterback’s new clean-cut look.

The coach explained that it was probably a good idea to represent the team in a different manner after being appointed the starter.

“I understand,” Whisenhunt said. “For a number of years, I made sure my son had his hair cut and was clean shaven, and the first thing when he got out on his own that he wanted to do was to grow a beard and let his hair grow long. But I also think you have to understand what you’re representing, and for lack of a better term, you’re a brand.”

REPORT CARD VS. TEXANS

–PASSING OFFENSE: C — QB Zach Mettenberger’s debut wasn’t the second coming of Dan Marino, but it wasn’t bad either. The rookie missed some throws in the first half and was put in some terrible down-and-distance situations because of penalties, but as the game wore on, he got more comfortable and played better.

–RUSHING OFFENSE: F — The Titans gained only 36 rushing yards and basically abandoned the run in the second half after the score got out of hand.

–PASS DEFENSE: D — The Titans sacked former teammate Ryan Fitzpatrick five times on Sunday, but the coverage in the secondary was spotty at times, and they got zero takeaways from a quarterback they know firsthand is turnover-prone.

–RUSH DEFENSE: F — RB Arian Foster produced 151 yards on 20 carries and also had two rushing touchdowns.

–SPECIAL TEAMS: B-minus — Dexter McCluster had a nice punt return to the 21-yard line to set the Titans up nicely on their first drive. However, the Titans managed just three points out of it.

–COACHING: C — The offensive game plan may have gone out the window when the Titans faced a big deficit, but Tennessee needed to have more runs to help balance things for a rookie quarterback making his first start.