KANSAS CITY, Mo. — Two transactions that the Kansas City Chiefs made before the start of the season came with little fanfare, mostly because casual football fans probably had never heard of either player.

Jordan Lucas was drafted in the sixth round out of Penn State by the Dolphins and had spent most of his career on their practice squad.

But when it became evident in late August that Kansas City might need help at safety, Chiefs General Manager Brett Veach sent a seventh-round pick to Miami for him.

Charvarius Ward went undrafted in April, overlooked by every team several times. He signed with the Cowboys as a free agent, then was shipped to the Chiefs for offensive lineman Parker Ehinger when Dallas decided it needed some help up front.

Two players, acquired one day apart, just may have turned a shoddy Chiefs defense into one that could carry the franchise to its first Super Bowl appearance in 49 years.

Lucas and Ward became dependable pieces in the Chiefs’ defensive backfield the final two weeks of the regular season. On Saturday, they helped shut down Andrew Luck and the Indianapolis Colts in a 31-13 victory that sent the franchise to its first AFC title game in 25 years.

“I think some of the young guys are maturing right in front of our eyes,” said Chiefs Coach Andy Reid, whose team will face the New England Patriots at Arrowhead Stadium next Sunday.

His defense had been seen as the biggest vulnerability all season, particularly as the offense shattered all kinds of franchise records. The only games the Chiefs lost came in shootouts against the Rams, Patriots and Seahawks, when their defense giving up a boatload of points, and when Kansas City couldn’t stop Philip Rivers and the Los Angeles Chargers in the fourth quarter.

It was after that game against the Chargers that Reid made a bold personnel move: He benched cornerback Orlando Scandrick and safety Ron Parker, a pair of veterans that had started all season, in favor of Lucas and Ware, a pair of relatively untested youngsters.

They had some growing pains the following week in Seattle, but Reid stuck with them, and they showed significant growth the following week. The Chiefs shut down Derek Carr and the Oakland Raiders in a Week 17 victory that they needed to wrap up the AFC West and No. 1 seed.

Their growth continued in leaps and bounds against the Colts.

Ward was picked on early and came up with several big breakups, and Lucas patrolled the middle of the field like a savvy center fielder. Together, they helped the Chiefs hold Luck to 203 yards passing and keep Indianapolis from scoring an offensive touchdown until late in the fourth quarter.

“At the end of the day, this is something we love to do, something we get paid to do,” Lucas said afterward, “so we have to go out there and give Chiefs Kingdom something we haven’t had in 25 years, and it’s special. We’re just looking to keep building.”

Part of the reason the defense has struggled all season is the fact that Eric Berry, a star safety and emotional leader, has been sidelined because of a heel injury. Berry tried to come back late in the season, only for the injury to flare up again, and he was inactive against the Colts.

Lucas has filled in admirably alongside Daniel Sorensen.

The improved play by the secondary has paid dividends up front, allowing defensive tackle Chris Jones and linebackers Justin Houston and Dee Ford to terrorize opposing quarterbacks.

“Very exciting. This is what we need as a team. This is what we work for,” Ford said. “We just want to keep this thing rolling. Enjoy it now but keep it rolling.”