NASHVILLE, Tenn. >> The Tennessee Titans know very well the value of having a quality backup quarterback.

This franchise has started one quarterback an entire season just once since the 2002 season and cycled through three different quarterbacks last year alone. It’s why the Titans drafted Marcus Mariota with the No. 2 pick overall even though they had Zach Mettenberger on the roster.

Having Mariota and Mettenberger both playing well this preseason makes the Titans more confident in that position, and less inclined to make a deal to a quarterback-needy team.

"We’re excited about Zach, he’s doing a nice job for us. We’re excited about Marcus Mariota," Titans coach Ken Whisenhunt said. "Our whole quarterback group has played very well. We’re completing almost 80 percent of our passes in the preseason, which is pretty astounding, so it’s a good problem to have."

Quarterback has been a rotating door for this franchise in recent years.

Mariota is the third quarterback drafted by the Titans in the first round in the past decade starting with Vince Young at No. 3 overall in 2006 and Jake Locker at No. 8 in 2011. That was the season Matt Hasselbeck started every game in a 9-7 season that remains Tennessee’s lone winning record since 2008.

Locker was benched after starting four of his first five games last season when Whisenhunt started veteran Charlie Whitehurst and then Mettenberger as a rookie and a sixth-round draft pick out of LSU.

Mettenberger became the sixth different quarterback to play for Tennessee over three seasons, but the 6-foot-5, 224-pound rookie didn’t win any of his six starts. With the second pick overall, the Titans went with the 6-4, 222-pound Mariota out of Oregon and turned the offense over to the rookie.

Mariota said Wednesday that Mettenberger has been a big help since he arrived.

"For him to just even welcome me in and help me out says a lot about who he is and his character," Mariota said. "I’ve been very fortunate to be a part of this quarterback unit. It’s a great group, and he’s done a lot to help my growth and help my transition."

Both quarterbacks are completing 75 percent of their passes through two exhibitions with Mariota 12 of 16 for 153 yards with one interception, while Mettenberger is 15 of 20 for 220 yards with two touchdowns and one interception. Their next game will be Friday night in Kansas City (2-0).

Whisenhunt said Mettenberger worked hard this offseason both to get stronger after an ACL injury in his final game at LSU and improve his game. The coach also said Mariota and Mettenberger genuinely like each other and laugh together.

"To me, he’s grown up as a pro, and that’s why I think he’s really going to be successful in this league at that position," Whisenhunt said.

Mettenberger is a cheap backup as well under contract through 2017. Paired with Mariota on his rookie deal, that puts the Titans in position to spend money elsewhere as they rebuild off last year’s 2-14 record. They currently have more than $20.9 million in salary cap space behind only Jacksonville and Cleveland, according to a report by the NFL Players Association.

But Mettenberger has looked so good that speculation already has started suggesting the Titans trade the backup to a quarterback-needy team. Whisenhunt remembers only too well what the Titans went through last season.

"I’m pleased with the competition," Whisenhunt said. "I think that makes everybody better. I like what I’ve seen on the practice field, but to do what they’ve done in the games, and I know it’s preseason and it’s not what you’re going to see in the regular season, but still … it feels good that we’ve got guys that are playing that way in preseason."

Notes: Mettenberger practiced Wednesday after missing Tuesday with food poisoning. RG Chance Warmack also practice returned to practice after having an ingrown portion of toenail removed from each foot. Rookie WR Dorial Green-Beckham did not practice after hurting his left ankle Tuesday, but he may play Friday at Kansas City.