"I'm the third corner that comes in," Rumph said. "I come in on third downs. If we're not making plays on third down, it affects me."
The Niners have been adversely affected by their defense not making plays on third down all season, and last Sunday it had a big affect on putting them in the loss column during their 35-27 defeat to the New Orleans Saints.
The Saints rallied from an 11-point deficit in the fourth quarter by converting 10 of 14 third-down attempts during the game. This continued a distubring trend for the 49ers that began in the season opener against the New York Giants, who converted 9 of 16 third-down attempts in that game. The Seattle Seahawks stayed close to the 49ers last week by converting 10 of 15 third-down attempts during San Francisco's 28-21 win.
"We have a good defense in a lot of different categories," Niners coach Steve Mariucci said. "We're so good on first downs and second downs. Where it's been biting us a little bit are third downs, and not third-and-shorts necessarily. Third-and-long and third-and-extra-long are situations people have been converting."
The Saints converted two third-and-12 plays during the final period, when they scored 22 points to erase a 24-13 San Francisco lead. New Orleans also converted on third-down distances of 14, 10 and 9 yards to keep scoring drives alive in the second half.
Mariucci said Sunday's breakdowns have convinced the Niners coaching staff to start looking more closely at alternatives to fix the problem.
"It just has to be a little bit more of a point of emphasis," Mariucci said. "We have a certain routine as to how we practice. But if there's a need, if there's an area of concern, we've got to be flexible enough to break away from what we do and give it more attention. So we'll do that. We simply have to make teams punt."
The Saints didn't punt once against the Niners. They produced 27 first downs and 422 yards of offense, each figure the most allowed by San Francisco in a game this year. That dropped the 49ers from eighth to 13th in the NFL this week in total defense.
Starting left cornerback Ahmed Plummer, the player opposing defenses are staying away from most often when they attempt to exploit the San Francisco secondary, said the Niners simply need to shore up on specific details in the secondary, which is struggling with techniques and assignments.
"We've looked at film, we see where we went wrong, and we're going to correct it," said Plummer, who knocked away two passes against the Saints. "It's just being sound fundamentally, just doing what we're coached to do. Everybody's got to be on the same page, and we're going to get it done."