Bobby April and his special teams units are building a bittersweet legacy in Buffalo.

For the fifth straight season they had one of the best special-teams records in the NFL. Yet once again the team could not parlay its overall kicking game excellence into a playoff appearance.

The Bills ranked among the top 10 by one measure or another in all four primary kicking and coverage categories.

Fans probably did not need to look at the statistics to see the Bills’ bomb-squadders getting the job done.

“If you notice, we usually gang tackle the opposing returner,” said April, the Bills’ special teams coordinator for the last five seasons. “The opponent usually has one guy tackling us. That’s a great indicator of how well you’re playing.”

Rookie Leodis McKelvin finished third in the NFL with a kickoff return average of 28.2 yards. The Bills’ average drive start after kickoffs (the 32.4 yard line) was the eighth best total this decade.

“He believes he’s taking every one back,” April said of McKelvin.

Buffalo’s Roscoe Parrish led the NFL in punt return average at 15.3 yards.

Overall on returns, the Bills were No. 1 on punts and No. 7 on kickoffs (although the average drive starting position is the more important figure).

On kickoff coverage, they ranked second in opponents’ kickoff return average and ninth in average drive start after kickoffs. On punt coverage they ranked 23rd in terms of opponents’ average punt return allowed. But in terms of net punting, which factors in the effectiveness of the punter and likewise is the better indicator of success, the Bills were seventh best in the NFL.

The only other teams that ranked among the top 10 in all four return-and-coverage disciplines, by one measure or another, were Oakland and Atlanta.

The showing was satisfying for the coaches because the Bills bid goodbye to four stalwart special teamers after last season — Coy Wire, Sam Aiken, Josh Stamer and Mario Haggan.

“The guys really did a good job, and a lot of them were playing for the first time,” April said. “A lot of times first-year players, even if they’re really good, it’s tough for them to play good. These guys for the first time playing have done a good job. They’ve played hard. They really scrapped. They get after it.”

April uses a complex grading system to measure the value of his players. Every man can earn points for doing his job on every special teams play. Players are awarded from three to 15 points for making a block. A solo tackle is 12. An assisted tackle is either five or eight. A touchdown return is 25. A game-winning field goal or a blocked kick is 30. A missed tackle is minus-5. And so on.

John Wendling was the points winner for the season among the coverage men. Second was Blake Costanzo and third was George Wilson.

Punter Brian Moorman, a Pro Bowler in 2006 and 2007, quietly posted one of his finest seasons. He had a career-best net average of 39.13 yards, which ranked eighth in the NFL. However, Moorman allowed fewer returns (just 31 percent) than any punter ranked ahead of him, and only one punter in the league, Atlanta’s Michael Koenen, had fewer punts returned than Moorman.

Oakland’s Shane Lechler led the league with a net average of 41.2 yards, an NFL record. Opponents returned 43 of Lechler’s punts for 425 yards. Opponents returned only 18 of Moorman’s punts for 187 yards, a career low. Moorman exposed his coverage units to far less risk than Lechler.

Kicker Rian Lindell had his worst field-goal percentage since his first year in Buffalo, in 2003. Lindell, who made a remarkable 86.9 percent of his attempts from 2004 to 2007, dropped to 78.9 percent this year, hitting 30 of 38. Lindell had one game-winning kick, a 38-yarder on the final play to beat the Raiders, 24-23. He also nailed a 45-yarder with 24 seconds left to help ice the 20-16 win at Jacksonville. His big miss was the 47-yarder that went wide right with 48 seconds left in the two-point loss to Cleveland.

“I think because of a crucial kick here and there that we really needed him to make, it kind of puts a little bit of a black eye on it,” April admitted. “But if you look at his whole body of work, he’s had a good year. He kicked off better than he usually does. No one’s heaping bouquets on him for hitting the last one against Oakland, but they’re sure putting the dagger in him for missing the one against Cleveland. . . . I understand that. That’s what he needs to do. But I’ve seen him do too many other good things for us over the years.”

Bills receiver James Hardy underwent surgery on Monday to repair the damage in the left knee that he suffered during the game at the New York Jets on Dec. 14, a team source confirmed.

Bills doctors performed the surgery to repair a torn anterior cruciate ligament. Hardy, the team’s second-round draft choice in 2008, will face six to nine months of rehabilitation in order to return to full action for the team. Hardy had nine catches for 87 yards and two touchdowns as a rookie.