A telling moment occurred on the Chiefs practice field last week when longtime left cornerback Brandon Flowers and veteran right cornerback Sean Smith switched sides for a day. It was Flowers’ first venture to the right side since his rookie season in 2008. Smith had played the left side in 2012 at Miami and was signed ostensibly to stop a revolving door at right corner. But it was a clear signal that the Chiefs are trying to do anything and everything to rebuild a secondary that not only hemorrhaged big plays last year but came up with few game-changing plays of their own. No longer will the secondary be subject to mismatches just because a shorter corner like Flowers is stuck on the left side against a taller receiver. Or if Smith is paired against a quicker receiver. Defensive coordinator Bob Sutton can pull the ol’ switcheroo. “We want to get comfortable on both sides of the field because we don’t know if some games we go into this season and we might match up with certain receivers” Flowers said. “We don’t want any side to feel foreign to us.” Sutton has brought an attacking defense based on pressuring the passer and playing tight man-to-man coverage on receivers as opposed to the zone schemes under former coach Romeo Crennel when the Chiefs pass defense was historically bad. A year ago the Chiefs surrendered 51 pass plays of 20 yards or more last season. That was 13th most in the league and of those plus-20-yard plays 14 were 30 yards or more; six were 40 yards or more; two were 50 yards or more and two both in the same game at Tampa Bay were 62 yards each. The Chiefs also allowed 29 touchdown passes — second-most in franchise history — and tied for fifth-most in the league. Many of the scores came early in games that put the offense in a come-from-behind mode. The Chiefs didn’t have a lead in regulation until the ninth game of the season. And worse the Chiefs’ pass defense failed to bail out the offense. The Chiefs intercepted just seven passes the fewest in franchise history and tied with Dallas for the fewest in the NFL last year. So Sutton brought what head coach Andy Reid called “a million different packages” involving his cornerbacks and safeties almost all with one-on-one principles to shore up the leaky pass defense.