Cardinals cornerback Justin Bethel shakes the hand of team president Michael Bidwill after Bethel signed a three-year contract extension Saturday.

The Cardinals have built their defense around their secondary, and Saturday, they took one step to making sure at least one piece remains in place.

Two-time special teams Pro Bowler Justin Bethel, who will be starting at cornerback for the Cardinals Sunday against the Rams in place of an injured Jerraud Powers, signed a three-year contract extension prior to the team's charter flight to St. Louis.

"With the guys we've got here, especially in our secondary, Pat (Peterson), Ty (Mathieu), Rashad (Johnson), Jerraud, Deone (Bucannon), Tony (Jefferson), all those guys, I think we have a really, really close group," Bethel told azcardinals.com. "It

shows on the field. Being able to get my deal done, and hopefully get some other guys done, is a really big deal to me.

"I'm just thankful I could stay with the team that drafted me."

The deal is worth $15 million, according to multiple reports, including $9 million in guarantees. It's possible Bethel could have earned more on the open market – a 25-year-old cornerback on the rise – but Bethel said he tried not to think about it much.

"You never know," Bethel said. "You want to stay with the team that brought you in. You talk with your agents, you talk with your family, you want to do what's best for you and your career. Not everybody plays the game for a long time. I didn't want to go and be greedy if they gave me a really good deal, which they did. I'm thankful."

Bethel said he wasn't sure what it means for his future in terms of the position he will play. Patrick Peterson is going to start on one side for the foreseeable future. Bethel could still surpass Powers on the depth chart in 2016, assuming Powers comes back.

Bethel was one of a handful of secondary components who are scheduled to have their contracts expire after the season. Powers will be an unrestricted free agent, as will Johnson. Jefferson is scheduled to become a restricted free agent.

Bethel has made his reputation on special teams; he is a leading candidate to earn that honor for a third straight season. But he has yearned to elevate his status to cornerback. He was unable to unseat Powers going into the season, but he will get a chance to show his progress while Powers is sidelined with a calf strain.

Team president Michael Bidwill talked about a contract extension as a promise of getting to the next level, something that guys like defensive tackle Calais Campbell and Peterson did after getting new deals.

"That's what the expectation is," Bidwill said. "We can't sustain success without players like (Justin)."

But Saturday, Bethel could only smile at the idea he was signing for millions after coming out of tiny Presbyterian College as an unknown sixth-round pick in 2012. He said one of his priorities with his new deal is to give back to both Presbyterian and his high school in South Carolina.

"The people who helped me get here," Bethel said. "I think it's a blessing for everybody."