Cardinals cornerback Justin Bethel played defense for the second half against the Ravens and will start his first game Sunday.

Justin Bethel's hundred-watt smile illuminated when he heard the question.

The Cardinals' fourth-year player is one of the marquee special teams players in the NFL, but he's yet to establish himself on defense. He will get that chance on Sunday against the Browns in his first career start at cornerback in place of the injured Jerraud Powers.

During Cleveland's three-receiver sets, Patrick Peterson will guard one wideout and Tyrann Mathieu another. It doesn't take a rocket scientist to figure out who the Browns will target the most.

"Of course," a smiling Bethel said when asked if he believes he will be tested. "That's what I want, though. I want them to give me a couple picks when I'm in there."

Bethel was a sixth-round pick of the Cardinals in 2012 as an unrefined ball of athleticism out of Presbyterian. He quickly became a force on special teams – he's made countless big plays, from blocking kicks to downing punts to forcing fumbles – but has never been more than a backup option on defense.

Bethel hoped to push for the starting outside cornerback role in training camp – which would have moved Powers to the slot – but coach Bruce Arians said the competition was "not very" close as Powers easily remained the starter. That doesn't mean Arians is worried about Bethel now.

"He should be plenty ready," Arians said. "He's had a ton of snaps. He's done a great job since he's been in there. He's got a pick-six (against the 49ers in Week 3), so he should be chomping at the bit."

Bethel has held up in coverage this year, albeit in a limited sample. According to Pro Football Focus, he's allowed four completions on nine pass attempts for 53 yards and has the interception. The big mistake came last week, when he played the wrong coverage and gave up an easy 31-yard completion to Chris Givens on Baltimore's final possession.

It's part of the learning curve at cornerback, a position Arians said can be difficult to master.

"It's very hard if you're playing a bunch of zone coverages with two-to-one reads and a lot of stuff like that," Arians said. "But when we play 'dude coverage' – 'I've got that dude, you've got that dude' – it isn't that hard."

The Cardinals could choose to help Bethel by shading a safety his way or playing mostly man coverage to ease the mental part, but Peterson said there won't be any changes to the defensive game plan.

"I'll still follow the No. 1 receiver and Justin will play off me," Peterson said. "We're going to stay aggressive. We're not going to try to cover up him being in there, because he's definitely a guy that can get the job done. We're not worried or nervous about having '28' out on the corner."

Arians said he is comfortable with Bethel as a starting cornerback, and even believes the team could handle one more injury at the position because of flexibility among the defensive backs. In a scenario in which Bethel or Peterson has to leave the game, Mathieu could move to cornerback full-time – leaving Tony Jefferson and Rashad Johnson at safety – and undrafted rookie Cariel Brooks would be the nickel corner.

Arians said it would take two injuries for the team to have to "spin the bottle" and tape together a secondary.

"A lot of our guys are interchangeable, so we're not panicking," Mathieu said.

Bethel will have his full allotment of special teams duties in addition to his work on defense, which will make him a busy man in Cleveland. He is prepared to take on both roles.

"I'll just do a little extra running in practice," he said.

He's certainly not mad at the arrangement. Bethel is well on his way to making a third straight Pro Bowl as a special teams ace, but wants badly to prove himself at cornerback (and it doesn't hurt that this is his contract year).

Wide receiver Larry Fitzgerald is the latest teammate to rave about Bethel's athleticism, and it seems everyone is excited to see how he holds up at cornerback.

"I remember the first time working out with him, the guy jumping on 60-inch boxes," Fitzgerald said. "The guy is unbelievably gifted in terms of that. And now, finally, getting his opportunity. We're going to only create more depth at that position. We're going to get Jerraud back in two weeks, and we're confident Justin can come in and fill in, play the position and build his confidence as well."