Antoine Bethea is understated as NFL personalities go. It’s easy to overlook the Indianapolis Colts safety on a defense with Pro Bowl stars Dwight Freeney and Bob Sanders.

But Bethea is playing the best football of his four-year career, by his account as well as teammates and coach Jim Caldwell.

When asked how he made the 2008 Pro Bowl as a second alternate — Sanders and Pittsburgh’s Troy Polamalu withdrew with injuries — Bethea acknowledges he would like to earn his way without the benefit of someone else stepping aside.

“Most definitely,” he said. “I’ll still take it any way it comes, but of course, it would feel better if I was named to the Pro Bowl.”

One season after leading the Colts with a career-high 126 tackles, Bethea again tops the list with 60 in the team’s 7-0 start. He also has two interceptions.

Sanders, who returned from knee surgery to start the past two games alongside Bethea, sees the improvement in his teammate.

" ‘Toine’ is definitely playing the best he’s played," the 2007 NFL Defensive Player of the Year said. “Every year, he’s gotten better and better and better and better.”

Bethea has been “the other guy” on the back line because so much is made of Sanders, be it for his ferocious hitting or continual buzz regarding injuries.

Bethea entered the league as an unknown, a sixth-round pick out of Howard. Yet while so many young players bide their time and wait for an opportunity, Bethea started right away, in 14 games as a rookie. He never has relinquished that spot, with 13 starts in 2007, 16 last season and all seven this year.

While Sanders missed 15 of the past 23 games with injuries, Bethea became the secondary leader. He doesn’t typically get noticed, unless it’s for a missed tackle.

“Year to year, that’s one thing I’ve always been critical of myself about, even though I’ve been high up there in tackles,” he said. "Watching tape and critiquing myself, there still were some tackles I’ve left out there.

“That’s one of the phases I thought I could improve in and, so far, I think I’ve been doing a better job of that.”

Bethea chided himself for missing a tackle on Frank Gore’s 64-yard touchdown run in Sunday’s 18-14 victory over San Francisco. True to his nature, he didn’t need anyone to bring it up.

“You’ve got to be critical of yourself in wins and losses,” he said. “There are still things I need to improve on.”

That’s one of the qualities Caldwell admires in Bethea.

“From the first moment he probably set foot on this location, he’s been a guy you could tell is very instinctive, very good work habits, a sure tackler, and he’s just continued to get better each and every year,” Caldwell said.

Bethea is in a contract year. Because Sanders is hurt so often, one would think the Colts will look to keep Bethea. They are the NFL’s No. 1 team in fewest points allowed (91) and, with a more aggressive blitzing scheme, it’s imperative the safeties are reliable.

“Being realistic, man, it’s there. I can’t lie,” he said of his contract situation. "But at the end of the day, if it’s meant for you to happen, it will come. If not, I’ll put my best foot forward and go along with it.

“Right now, I can’t think about that. It’s a team game right now. The big goal is to get the Super Bowl and get another ring. Forget about all the individual stuff.”