Two years ago, the New York Giants lost Tiki Barber to retirement. This year Michael Strahan retired and Osi Umenyiora was hurt in preseason, depriving them of their star defensive ends. Then they traded tight end Jeremy Shockey, who was injured in 2007 and missed the playoffs.

All they did was win the Super Bowl last season. Now they’ve raced to an 11-1 record, a win away from the NFC East title and maybe another from home-field advantage in the playoffs. If they beat Philadelphia on Sunday, it will be their seventh straight victory over a team with a winning record, a mark that indicates they are close to dominant.

So why should they miss Plaxico Burress after he somehow managed to shoot himself in the leg Nov. 29 in a New York nightclub, getting himself suspended by the team and, for good measure, placed on the non-football injury list? That guarantees he will miss the rest of the season.

They won’t miss him, at least not for the immediate future.

This year, for example, Burress has missed by suspension or injury all but one series in three games. New York won the three by a total of 62 points: 44-6 over Seattle; 23-7 in Washington last week; and 37-29 in Arizona, when Plaxico had to leave early with a hamstring problem.

In fact, the Giants are so deep at receiver that they’ve been unable to play guys they want to because they can only get so many on the field at one time.

Take rookie Mario Manningham, the team’s third-round draft pick in April. So far he’s been active for just three games and caught one pass for 6 yards.

“Mario was dressed last week. Had it come to that, I was confident that he could (do well),” coach Tom Coughlin said this week. “We had a couple of things in for him that we just didn’t get to.”

But it goes way beyond Manningham or Domenik Hixon, who started in Burress’ place in Washington last week and had five catches for 74 yards. And well beyond the receiver position.

It goes to an organization that drafts and scouts so well that it always seems to be able to plug in someone unknown for a “name” player who retires or gets hurt, or aggravates Coughlin and/or the front office and is dumped. (The Giants suggest Burress could be back next year, although past practice indicates otherwise.)

The operative case is Shockey, the talented but obstreperous tight end who broke his ankle late last season, then sulked as Kevin Boss, a fifth-round draft choice, performed admirably in the playoffs and Super Bowl. The Giants welcomed back Shockey this year, but when he continued to grouse, traded him to New Orleans for second- and fifth-round picks.

Playing in a pass-oriented offense piloted by Drew Brees, who might break Dan Marino’s single-season record for yards passing, Shockey has 39 catches for 371 yards, a 9.5 average and NO touchdowns. Playing in a run-oriented offense, Boss has 26 catches for 310 yards, an 11.9 average and FIVE TDs.

Hixon, picked up off waivers from Denver last season, got a chance to work with Eli Manning and the first unit in training camp while Burress was either nursing an ankle injury or holding himself out of workouts for the lucrative contract extension he eventually got.

It helped get Hixon familiar with the starting QB and certainly has helped him during the regular season. Hixon has 15 catches for 230 yards in the games he’s replaced Burress, and 26 for 373 yards and a 14.3 average overall. In the Arizona game, he had 258 net yards, including kickoff returns of 83 and 68 yards.

And when he missed the second half of the Seattle game with a minor injury, in stepped another guy who’s had trouble getting on the field: Sinorice Moss, a second-round pick in 2006. He finished with four catches for 45 yards and two touchdowns.

All these players are produced by what has become one of the top organizations in football — put New England and Pittsburgh up there, too. “Every time I call to check on a player I’ve heard about, I find the Giants already have been there,” says Gil Brandt, the former personnel director of the Cowboys and the NFL’s chief scouting advisor.

That doesn’t only apply to colleges.

Hixon, for example, was chosen in the fourth round of the 2006 draft from Akron by the Broncos.

But in the opening game last season, he was the return man tackled by Buffalo’s Kevin Everett, who broke his neck on the play and was left paralyzed for a while. Upset, Hixon brooded, his play suffered, and the Broncos tried to sneak him through waivers and on to the practice squad.

The Giants pounced.

They do that a lot.

Derrick Ward, the “Wind” of the “Earth, Wind and Fire” backfield that leads the league in rushing, was picked up off the New York Jets’ practice squad in 2004. Last year, the Giants claimed Danny Ware from the same place, and he made a team loaded with running backs in training camp this spring, another “Wind” or “Fire” in training. Remember, the Giants were the team that didn’t have room in the backfield for Ryan Grant and traded him to Green Bay for a sixth-round draft choice a year ago. Grant rushed for 956 yards and eight TDs for the Packers in 2007.

When fullback Madison Hedgecock was released by St. Louis early last season, New York grabbed him. He’s turned into the sixth member of the NFL’s best offensive line, his blocking one of the reasons the Giants have led the league in rushing virtually all season.

Dave Tollefson, plucked last season off the Oakland practice squad, has helped fill in for Umenyiora as a regular member of the defensive line rotation. He has 31⁄2 sacks, fourth on the team behind Justin Tuck, Fred Robbins and Matthias Kiwanuka. Another ex-Raider is backup offensive lineman Kevin Boothe, who the Giants deem perfectly capable of filling in if one of their starters goes down.

There’s a theme there, especially when it pertains to teams like the Rams or Raiders.

How can a bad team overlook or cut (Boothe), a player who proves valuable to a Super Bowl champion? Easy. The good teams have sharp scouts and complete files on every player who’s ever been on the NFL’s radar. The bad ones work on whim, especially in Oakland, where the great overseer spends millions on injured and/or flawed former high draft choices and hires coaches who don’t notice lower-rated players who can be useful as pass rushers or backup offensive linemen.

But back to the Burress situation.

For now, the Giants are fine with a receiving corps of Hixon, Amani Toomer, Steve Smith, Boss, Moss and Manningham.

In the playoffs, it might get harder, when opponents don’t have to double-team Burress and manage to play an extra run-stopper while covering the other guys with one DB each. And scoring could be harder with no 6-foot-5 wideout to throw to near the goal line, although Boss has proven himself effective in those situations.

On the other hand, Hixon’s stats in limited appearances suggest he just might have to be double-teamed.

Just another example of why good teams continue to thrive and bad ones continue to, well, be bad.