Sean Smith backpedalled into the end zone with the scout-team wide receiver, careful not to lay a hand on him. When the quarterback let go of the ball, the Chiefs' cornerback quickly jumped on it, snapping it away for an easy interception.

It was perfect coverage. Perfect technique.

It was an important play for Smith to make in more ways than one.

Not only is the veteran cornerback trying to win back his starting job in a defensive backfield that is still unsettled, he's trying to do it while adjusting to the league's renewed emphasis on illegal contact and holding that is making life harder than ever for players at his position.

''You have to learn how to use your feet, especially if you're going to press,'' Smith said. ''They're going to let you get one good pop, and from there on, hands are off. You have to put yourself in good position.''

Total penalties are up nearly 44 percent from the first two preseason games last year, according to figures released by the NFL. More specifically, there have been 55 illegal contact penalties compared to eight last year, and 107 holds compared to 20 during the 2013 preseason.

''The biggest thing, you don't want to stop being aggressive,'' Smith said. ''That'll change your whole game. You still want to be physical.''

That rings especially true in Kansas City, where general manager John Dorsey and coach Andy Reid tend to favor bigger, more physical defensive backs over smaller, quicker ones.

''Your technique has got to be on point,'' fellow cornerback Chris Owens said. ''What happens, especially for me and I can only speak for myself, if you mess up on your technique you start to grab and pull, so you've got to be sound with your technique.''

That physical nature is a big reason why Smith was brought in last year. At 6-foot-3, 218 pounds, he's among the biggest cornerbacks in the league, and his ability to give wide receivers a legal mugging at the line of scrimmage is what has made him successful throughout his career.

Now, his ability to adjust to the changing rules could be a factor in just how much he plays this season. Smith had been shuffled down the depth chart early in camp, and now he's trying to work his way back as the Chiefs attempt to find a starting defensive backfield - a problem that has been compounded by the loss of Pro Bowl safety Eric Berry to a nagging heel injury.

In that pursuit, the Chiefs traded backup offensive lineman Rishaw Johnson to Tampa Bay on Thursday for Kelcie McCray, who has played with the Dolphins and Buccaneers the past two seasons.

''We're going to roll them through and keep going,'' Chiefs defensive coordinator Bob Sutton said of his defensive backs. ''Each of them has had some really good plays and probably some they could do better. But I think the competition has been good, and we're going to need all those guys.''

Marcus Cooper and Ron Parker started at the two cornerback spots early in camp, and Smith has barged back into the conversation. But there is precious little depth behind them, which means the Chiefs could be scouring the waiver wire after the first round of cuts next week.

Behind them, Husain Abdullah has held down the free safety job and Berry is expected back by the regular season. But if he can't go, undrafted rookie Daniel Sorenson and journeyman Malcolm Bronson are the two most likely candidates to get the nod.

Not exactly encouraging in the flag-filled world of the NFL these days.

''It's being called real tight and we knew that coming in,'' Chiefs coach Andy Reid said. ''It sounds like they're going to continue to call them, and you just hope it doesn't turn spectators from the game. They get bored watching the officials throw the ball more than the quarterback.''

Notes: RB Jamaal Charles (foot) returned to practice for the first time in a week, though he is unlikely to play Saturday night against Minnesota. RB/WR De'Anthony Thomas (hamstring) also returned to practice. ... Berry, WR Dwayne Bowe (quad) and Joe Mays (wrist) were among those who did not participate in the workout.