IRVING, Texas -- The Cowboys offensive tackles, Doug Free (right) and Tyron Smith (left), have improved their play the last couple of weeks.

Quarterback Tony Romo wasn't sacked last week at Carolina and the Panthers weren't credited with any quarterback hits.

Everything could change Sunday afternoon at Cowboys Stadium when the New York Giants come calling. In the first meeting, the season-opener, Romo was sacked twice and knocked down twice.

The Giants edge rushers, Justin Tuck, Jason Pierre-Paul and Osi Umenyiora are difficult to defend for any offensive line.

Pierre-Paul leads the Giants with 4.5 sacks and five quarterback hits. Tuck recorded his first sack of the season last week against Washington, but he's got three quarterback hits. Umenyiora has three sacks on the season, second on the team, and four quarterback hits.

"We went into Carolina and we were challenged," Cowboys offensive line coach Bill Callahan said. "We had too many penalties the week prior to that. We felt the week coming out of the Baltimore game, we did better with the presnap penalties and then we went the last game and we did well. From their prospective they’ve shown some improvement, in terms of shutting down the edges. We've been challenged by some really good rushers and the challenge is greater this week when you look at these guys from New York, this is what they do. This is the heart of their defense we’re challenged again."

Penalties are the biggest issue for the tackles.

Free leads the team with nine penalties for 60 yards and had a four-penalty game in Week 4, which included three false starts. Free leads the NFL with six false starts overall and he's tied for sixth with three holding calls.

Smith has eight penalties for 46 yards charged on his 2012 resume. In that Week 1 game against the Giants, Smith was flagged four times, three on false starts.

Smith is second in the NFL with five false start penalties.

When the Cowboys run, they're averaging 5.84 yards per carry going off left tackle, seventh in the league. But when run plays go toward Free's side, the team averages just 2.83 yards per carry, 28th in the league.

"We're getting into a rhythm and we’re getting into a routine of what we want to establish," Callahan said. "It's really not that much different from what (former offensive) coach (Hudson) Houck did. The footwork is improving, their angles are improving and whatever line coach there is will tell you, you can always improve your hands, your punch, your stride all those fundamental type things to shut down a great edge rusher."