SANTA CLARA — Among the factors that could swing the 49ers' NFC divisional playoff game against the Saints today, it's possible that the most important is also the most down-to-earth. It's there beneath your feet when you take a walk in the park, and it's staring you in the face when you plop down to rip out dandelions in the spring.

It's grass, and it has never smelled sweeter to the 49ers.

The New Orleans Saints had a devastating offense this year, setting an NFL record with 7,474 yards from scrimmage and finishing just behind the Packers with 547 points. But a closer analysis reveals that the Saints weren't the same team on natural grass that they were on artificial surfaces.

"I didn't think that, but I think so (now), because you just look at their home and away games, especially in a dome, inside. Outside on grass it's not the same," 49ers cornerback Carlos Rogers said at his locker earlier this week. "I hope they continue that this week, but you never know."

The Saints weren't operating on level playing fields this year. Their yardage total was largely unaffected — they averaged 469 per game on plastic, 462.8 on grass. But Brees' passer rating dropped off significantly on grass surfaces, 95.7 compared to 118.7 on artificial fields, as did New Orleans' scoring average, 25.8 points compared to 38. Most important, the Saints were 10-1 on man-made surfaces (including 8-0 at home in the Louisiana Superdome), 3-2 on the lawn — with victories at Jacksonville, Carolina and Tennessee, and losses at Green Bay and Tampa Bay.

Not surprisingly, both coaches downplayed the significance.

"There's been some talk about maybe those (losses) were the road games or that kind of talk. But those were early ... in the season," San Francisco's Jim Harbaugh said. "This is a good road team. They were 5-3 this year. They were 6-2 the year before on the road. Before that, I think they were one of the best road teams in the league."

Niners center Jonathan Goodwin spent five years with New Orleans, including the Super Bowl championship run in 2009, and he didn't have any encouraging word about the Saints' mindset on grass.

"It wasn't even said down there," Goodwin observed. "We felt like wherever we went, every time we got in the huddle we should score. Obviously, that's what it looks like they're thinking now. I don't think that will be something in their head that they will be fearing anything."

Add Troy Aikman's voice to the chorus. The Fox NFL analyst spent his Pro Football Hall of Fame career quarterbacking the Cowboys on the artificial turf of old Texas Stadium, and he doesn't believe Brees and company will be thrown off by a little dirt between their cleats.

"I don't put any stock in those things," Aikman said. "I mean, are you faster on turf? Are you faster indoors? Do you throw the ball better indoors? Yeah, of course you do, as opposed to having to deal with the elements or having to deal with the wind, and now you're wearing cleats instead of tennis shoes indoors. Those things affect you to some degree, but to say that it's a measurable difference, I've never bought into that."

Aikman raises a good point. Getting a dome team outside might be a big deal if you're talking about the frozen tundra of Lambeau Field. The temperate soil of Candlestick Park isn't quite as intimidating.

"You always worry about the footing: How's the grass? How's the turf?" Brees said. "It's different when you're playing on the West Coast, that type of grass as opposed to maybe up north where it's been snowed on or it's icy or frozen, or been torn up, that kind of thing. So that's just something, you go out beforehand, make sure you have the right cleats and all that stuff. If there's any weather conditions — wind, rain, snow, whatever — that you have to take into consideration."

Alas, the weather report for today predicts sunshine and high temperatures in the mid-60s, with 0 percent chance of rain. None of those famous winds, just one dangerous Brees. Saints coach Sean Payton said his team would practice outside on grass Wednesday and Thursday, and at Candlestick on Friday.

There is one theory for the grass/turf differential that makes sense, and it has to do with the precision clockwork of the Saints' passing game. As 49ers defensive lineman Justin Smith explained: "The way they throw the ball — we were watching today, and have seen it throughout the course of the year. Their timing routes, their back-shoulder fades — we pause the film, the ball's halfway down the field and the guy's still running straight."

The whole operation is based on timing — the timing of Brees' drop, the timing of his release, the timing of the receivers' cuts. Those acts are slightly faster on a more stable surface, even if the difference is measured in milliseconds. And if the Saints play most of their games, and spend most of their practice time, on artificial turf (the product at the Superdome is called Sportexe Momentum), it stands to reason that their timing is synched to that surface.

That was cornerback Tarell Brown's best guess, anyway. "I'd say those guys are just used to it," he said. "You're comfortable with your home-field surface, so those guys do a great job of adjusting to the surface they play on all the time, so it's consistent for them."

Then he added: "But I don't think it's that big of a difference."

Which is probably true. When it comes down to it, the 49ers biggest advantage at Candlestick won't be the grass under their shoes, but the sea of red jerseys in the stands. And that might be the real explanation of the Saints' slow-down on natural fields.

"To get 'em outside of the dome, that's a big thing for us," said nose tackle Ricky Jean Francois, who played at LSU. "Because, you know, you got Drew inside there, you got the second line band, you got Mardi Gras, you got everything going on in there. And that's his place. So just to get him out of his area and bring him out of doors, it might be an advantage."

And against this record-setting aerial attack, the 49ers will take every advantage they can get.

You can reach Staff Writer Phil Barber at 521-5263 or phil.barber@pressdemocrat.com.