SAN DIEGO -- Just two seasons ago, getting inside the opponents' 20-yard line was the "Gold Zone" for the Chargers' offense. It was an area of the field where riches like touchdowns routinely followed.

But now that part of the gridiron has become the "Dead Zone," a place that more often than not doesn't result in adding seven points to the scoreboard.

Sure, Shawne Merriman's season-ending knee surgery and referee Ed Hochuli's botched call in Denver are big factors in why the Chargers limp along with a 4-7 record in late November, but the lackluster red zone performance also has been a major factor.

The Chargers, who led the NFL in touchdown percentage inside the red zone (67.7 percent) in 2006 under former coach Marty Schottenheimer, are just 26th in the NFL in converting their voyages inside the 20 into touchdowns this season.

Second-year coach Norv Turner's offense has scored just 20 touchdowns in 42 opportunities and has settled for field goals 17 times. The offense has failed to score a point five other times.

In the world of the NFL, where games are often decided by slim margins, that 47.6 conversion rate represents a lot of squandered points. And seeing that the Chargers' seven losses are by a combined 28 points, with four games decided by three points or less, it's clear the failures are a prime reason for the team's underachieving record.

"Just look back at points in the games that came down so close to the wire," quarterback Philip Rivers said. "You look at what a touchdown opposed to a field goal could've meant late in a game.

"You're not going to score a touchdown every time, and we're going to need those field goals too. We need to score points down there.

"Those points, you could say, have been the difference in games."

They certainly have. In the team's two one-point losses, the Chargers scored just two touchdowns in seven red-zone opportunities.

Against Denver, they went 1-for-4 inside the 20, and settled for field goals after having first-and-goal situations at the Broncos' 5 and 11 yard-lines.

Against Pittsburgh, they were 1-for-3 with Rivers throwing a costly interception when the Chargers had first-and-10 at the Steelers' 17.

Last Sunday's three-point loss to Indianapolis was another time when a red zone opportunity eventually became the difference between winning and losing. With the score tied at 10, the Chargers began the second half by reaching the Colts' 9.

After a false start penalty by Jeromey Clary pushed the ball back five yards, Rivers was sacked and fumbled when Robert Mathis rushed past Clary and stripped Rivers of the ball. The Colts recovered and later kicked a game-winning field goal on the game's final play, which magnified the missed opportunity.

"We've been in too many situations the last month where we've ended up with no points," Turner said.

Turner's not kidding. The turnover was the team's third inside the red zone in a five-game span, dating back to when Rivers was intercepted by Buffalo linebacker Kawika Mitchell on first-and-goal from the Bills' 9 in the fourth quarter of a mid-October contest.

And two weeks before that, the Chargers lost by seven points to Miami with the crucial play being when LaDainian Tomlinson was stopped for no gain on fourth-and-goal from the Dolphins' 1.

"Right now, we can get better and we understand that," tight end Antonio Gates said. "We're nowhere as efficient as we want to be in the red zone, and it shows.

"You look at games and there are situations we got down there and we had turnovers and that's not the emphasis of what we need to do."

Last season, the Chargers converted 55.8 percent of their red zone chances into touchdowns, a figure that ranked 11th in the NFL. They turned the ball over just once and that came on a highly disputed play in the season-opening game against Chicago, when they had the ball at the Bears' 1.

While anticipating the snap, Chicago defensive tackle Tommie Harris appeared to have jumped offsides and he plowed into Rivers, forcing a fumble that Chicago safety Mike Brown recovered.

This season's struggles are hard to explain, but the Chargers haven't run the ball nearly as well as they once did. Tomlinson, who rushed for 28 touchdowns two seasons ago, has just five rushing scores this season.

He's also at a loss when given his opportunity to sum up the team's demise in red zone efficiency.

"I don't know," Tomlinson said. "For one, the teams we are playing are much better, obviously, but I think some of that is teams' game plan. (They) kind of buckle down when you get into the red zone and try to keep us out of the end zone.

"Teams are doing a good job of stopping us from scoring touchdowns."

Rivers, Gates and Turner all cited execution issues. In fact, Turner thought the Chargers could have scored a touchdown against Indianapolis on one of the two running plays before Rivers' lost fumble.

"We had two plays Sunday that we were one block away," Turner said. "If you look at it from the end zone, it looked like (Tomlinson) is going to walk into the end zone.

"We've got to execute better. We obviously tried to run the ball. We need to run the ball better and then the biggest thing, we can't turn the ball over down in there."

The Chargers were 1-for-3 in the red zone against Indianapolis, which ironically has the NFL's most efficient red-zone offense. The Colts have scored touchdowns on 23-of-32 possessions, a league-high 71.9 percent.

The Chargers aren't going to get anywhere close to that level this season. Or even approach their 2006 form of 67.7 percent, when they scored a league-high 42 red-zone touchdowns in 62 chances.

But everyone will tell you that improvement is necessary over the final five games of the regular-season if the Chargers are to be participating in January' s playoffs.

"You want to be efficient in the red zone," Gates said. "That will win games for you. We know that and we understand that."

Contact staff writer Mike Sullivan at (760) 739-6645 or msullivan@nctimes.com.