There are plenty of theories going around on what ails the 2-5 Steelers. They are slow starters, allow too many big plays on defense and can't run the ball on offense. All that is true, but the inability to score and prevent touchdowns in the red zone is as big a problem as any for this team.

As the Steelers approach the halfway point of the 2013 season, they are 30th in the NFL in red-zone offense. Only the winless Jacksonville Jaguars have a harder time scoring touchdowns in the red zone than the Steelers.

The Steelers are 13th in the league in red-zone defense, which is about where they have been the past two seasons but well off their percentages from their two most recent Super Bowl years in 2008 and 2010 when they were top-five in the league.

The 21-18 loss last Sunday at Oakland was a good example of how inefficiency in the red zone created problems the team could not overcome. The Raiders penetrated the Steelers 20 twice in the game and came away with touchdowns both times. That led to an early 21-3 deficit.

"Had we forced them to a field goal in either of those trips down, we probably would have won the game," defensive coordinator Dick LeBeau said. "That's why the red zone is so important. We will see where we are at the end of the year. I think our guys play pretty good. I think they understand the problems down there."

The Steelers still rank as one of the top teams in the NFL in total defense, but where they once succeeded in holding teams to field goals they are now surrendering touchdowns with more regularity.

Opponents have scored 16 touchdowns in the first seven games. The defense has been responsible for 14 of those (two were defensive touchdowns -- an interception return and a fumble return in the loss to the Bears).

In 2010, when they were AFC champions and lost to Green Bay in Super Bowl XLV, the Steelers allowed 22 touchdowns in 16 regular-season games. In 2008 when they won Super Bowl XLIII, they allowed 21.

The offense has even bigger issues in the red zone. Against the Raiders, the Steelers got inside the Raiders 20 on four occasions and came away with touchdowns twice. That's actually higher than their season percentage. They have scored touchdowns on 40 percent of their trips inside the red zone. Last season, Todd Haley's first as offensive coordinator, they converted at a 55 percent clip.