ORCHARD PARK, N.Y. — Quarterback A.J. McCarron is eager for the opportunity to prove himself with the Buffalo Bills after spending the previous four seasons working in Andy Dalton's shadow.

And it makes no difference to McCarron if the Bills add more competition should they select one of the highly regarded quarterback prospects in the first round of the draft next month.

"I try not to ever waste any mental thought on it because it's something I can't control," McCarron said Thursday, after arriving at the Bills facility to officially sign his two-year contract.

"There's no reason for me to really put any thought into it just to be honest with you, because it creates mental clutter for my process that I need to be the best player I need to be."

The 27-year-old said he's not affected by the perception of Buffalo signing him to hold down the starting job on a short-term basis and allow time for a younger quarterback to develop.

"You can either let it affect you in how you go about your work and let that define you. Or you can change everybody's thought process," McCarron said. "My mindset is to change anybody that's had any doubt."

For now, McCarron and 2017 fifth-round draft pick, Nathan Peterman, are the only quarterbacks on Buffalo's roster after the team traded third-year starter Tyrod Taylor to Cleveland last week.

Buffalo is considered among the teams targeting a quarterback in the draft. The Bills have two picks in each of the first three rounds — including the 12th and 22nd overall.

McCarron was a two-time national champion at Alabama but appeared in just 11 games in Cincinnati, mostly in mop-up duties. McCarron did start the final three games of the 2015 season and led the Bengals to the playoffs after Dalton broke his thumb.

He was on the verge of leading the Bengals to their first playoff win since the 1990 season before Jeremy Hill's fumble and two penalties allowed Pittsburgh to secure an 18-16 win in the AFC wild-card game.

McCarron is now part of the Bills' ongoing roster overhaul in being one of five newcomers to join the team once the NFL's free-agency period opened Wednesday. The others are defensive tackle Star Lotulelei, former Washington pass-rushing specialist Trent Murphy, safety Rafael Bush and linebacker Julian Stanford.

Also on Thursday, the Bills freed up salary cap space by restructuring the contract of veteran offensive guard Richie Incognito.

Lotulelei and Murphy are key additions for the Bills in overhauling a defensive front seven to shore up a unit that ranked 29th against the run and finished tied with the third-fewest sacks at 27.

Lotulelei signed a five-year contract after spending his first five seasons with the Carolina Panthers. The 28-year-old is reunited with Bills coach Sean McDermott, who was the Panthers defensive co-ordinator before being hired by Buffalo in January 2017.

Lotulelei expects his familiarity with McDermott's defensive philosophy to ease his transition. He's also looking forward to the chance to line up alongside respected veteran Kyle Williams, who signed a one-year contract this week to return for a 13th season.

"Kyle Williams, I've been a big fan of his," Lotulelei said. "Coming here and having the opportunity to learn from him as well as play alongside him will be great."

Murphy was so eager to get to Buffalo, he drove overnight through a snowstorm. He arrived at about 1:30 a.m. in making the 320-mile trip from Columbus, Ohio, where he spent the past 10 weeks working out to strengthen his injured left knee. The fourth-year player missed all of last season after tearing two ligaments during Washington's first preseason game.

The injury came after the former second-round draft pick had a career-best nine sacks in 2016. Murphy, who signed a three-year contract, is motivated to prove he can return to playing at the same level.

"I couldn't be more exited to prove everyone here right that I'm who they think I am," he said. "It's just more motivation to grind out the rest of this off-season and get here and get working."

Murphy said he is on track to be fully healthy for the start of the season.

McCarron is getting a fresh start after being nearly traded to Cleveland last season. The deal fell through after the Browns failed to submit the paperwork on time.

And he only became eligible to enter free agency after an independent arbitrator last month ruled McCarron's rookie season counted toward his NFL tenure even though he spent a majority of the year on the non-football injury list because of a sore passing shoulder.

"It's been a little bit of a roller coaster," he said.

"We get impatient and you want things fast and easy, but it's not always that way," McCarron said. "So I think it just adds another chapter to the story in the end. It's just part of the process. It's awesome to be here in this situation now."

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