Saints cornerback Corey White couldn’t stop himself from feeling the same way he has throughout his athletic career.

He watched the Saints sign a 12-time Pro Bowler and a second-round draft selection at his position group during this offseason. As usual, he felt overlooked.

“I’ve been underestimated — in my opinion — all my life,” said White, who grew up in a small suburb north of Atlanta and attended college at Samford, a member of the NCAA’s Football Championship Subdivision. “I went to a small school. I grew up in a small neighborhood. ... Of course I’m going to be thinking, ‘They don’t believe in me.’ ”

But the future Hall of Famer, 36-year-old Champ Bailey, didn’t make the roster. The rookie, Stanley Jean-Baptiste, has been inactive for the Saints’ first three games this season. And the man New Orleans hoped would be the outside cornerback opposite entrenched starter Keenan Lewis — veteran Patrick Robinson — was demoted after struggling.

White, therefore, was back Wednesday where he ended his second year with the Saints in 2013: as a starter. It’s an opportunity he said he earned for himself by ignoring factors he couldn’t control (namely, the Saints’ personnel decisions) and fixating on what he could: his performance.

“I’ve been working — not thinking of who’s ahead of me, thinking about who’s coming in,” White said. “I don’t count numbers. I just play football.”

As the former fifth-round draft choice entered his second season in the NFL and with the Saints in 2013, White was firmly the fourth cornerback, under outside guys Lewis and Jabari Greer as well as slot man Robinson.

However, Robinson suffered a season-ending knee injury in a Week 2 victory at Tampa Bay. Greer subsequently suffered a career-ending knee injury during a Week 12 victory at home against San Francisco. And White suddenly was the No. 2 cornerback.

The Saints won three of the seven regular-season games and one of the two playoff contests for which he was the No. 2 cornerback. Quarterbacks had a worse passer rating throwing against White (91.1) than they did Greer (93.3), according to the website Pro Football Focus. They had a worse passer rating throwing against White than they did versus Bailey (96.1), who was with Denver in 2013 and signed with the Saints in April.

Nonetheless, when the Saints’ training camp began in July, it was Bailey and a healed Robinson — the No. 3 cornerback at the start of 2013 — competing to start opposite Lewis. Robinson triumphed in that audition; Bailey was released; and White opened this season as the No. 3 cornerback.

Only Robinson soon struggled, surrendering receptions of 35 and 27 yards on drives resulting in Falcons touchdowns during a 37-34 setback in Atlanta in Week 1. He gave up a TD and drew three penalty flags in a 26-24 defeat at Cleveland in Week 2.

The Saints could no longer delay giving White a bigger role. Early in the Cleveland game, they tasked White with lining up outside opposite Lewis in their base defense, though Robinson still rotated in on certain packages.

In a Week 3 outing at home against Minnesota, Robinson logged a single snap on defense. White was Lewis’ outside complement throughout — and the Saints won 20-9.

White had made the switch inevitable. He had recovered a fumble in Atlanta. That was merely the fifth turnover the Saints have created in their last 12 regular-season games, and White had accounted for three of them.

White was first on the team in tackles with 13 (all solo) heading into Week 3 and was second with 15 afterward.

Though Pro Football Focus calculated that White had permitted 116 yards and 14 catches off 18 passes tossed his way in Weeks 1 and 2, he allowed no receptions against Minnesota, utilizing tight coverage to force a deep overthrow the one time he was really challenged.

White and his team Wednesday realized he’s in for a big test when the Saints visit the 2-1 Cowboys and Pro Bowl receiver Dez Bryant in Dallas on Sunday. But he deserved his climb up the depth chart, they said.

“He’s got a real good football sense as to what’s going on,” Saints coach Sean Payton remarked. “His tackling ability, and his ability to cover, all of those things have helped him.”

Saints safety Kenny Vaccaro added: “He’s strong, physical ... and has some of the best ball skills on the team. He’s confident. He has all the tools to be a top corner in this league. He just has to put it together.”

And, while he strives to do that last part, it won’t bother White that it wasn’t necessarily Plan A.

“That’s the business of football,” he said. “And ... you can’t let business get personal.”