Nose tackle Dan Williams collapses the 49ers' run blocking during last year's game in San Francisco.

When Todd Bowles arrived as defensive coordinator, he studied the Cardinals' defense as a whole and never truly broke down the unit when it came to holding up against the run.

But the Cardinals were 28th against the run a season ago. This year, after five games, they rank third against the run – an improvement that figures to play a key role in Sunday's NFC West game against San Francisco.

"I just know the guys this year, we are trying to make sure they are fundamentally sound and not take off and rush the passer every play," Bowles said. "That's not a comparison to last year. That's just what we teach."

There are personnel changes that have helped. The addition of Alameda Ta'amu at nose tackle with Dan Williams provides heft on running plays even if one or the other needs a break, depth the Cards didn't have last season. Newcomer Matt Shaughnessy, who has played defensive end,

playing linebacker has made the Cards more stout on the edge than they were last season.

"I think we have better athletes and obviously bigger linemen who can move and play sound football," linebacker Daryl Washington said. "I think this is the week right here, where the last two games they don't even count if we can't take care of this one. It starts up front. We have to take care of the run."

The Cardinals stuffed Tampa Bay running back Doug Martin two weeks ago (only 45 yards on 27 carries) and then kept DeAngelo Williams to 3.3 yards a carry against Carolina. Both teams liked to rely on the run.

But neither is as good as San Francisco.

The 49ers, coming off a bad home loss to the Colts, played a Thursday night game in St. Louis and went scoreless for a quarter as Kaepernick continued to be erratic. So San Francisco, which had been running the ball well, turned to a heavy ground game and the offense has been on a roll since.

The 49ers had 40 rushes (for 219 yards) against the Rams compared to 23 passes, and in a win against the Texans, Kaepernick threw just 15 times with the 49ers running 36 times. Some of that was dictated by the lopsided scores, but the Niners seem to have gotten back to their roots when coach Jim Harbaugh first took over and Alex Smith was the quarterback.

"There has been no shift," Harbaugh said. "We seek to be balanced, 50-50 in the run-pass. Sometimes game situation dictates heavier one way or the other, but there's been no shift."

Perhaps not, but the Cards know their run defense will be tested often Sunday.

"(The 49ers) tell you exactly what they are going to do and it's going to be on us if we are going to stop it," Washington said. "It's not going to be complicated at all what they do."

FITZGERALD QUESTIONABLE FOR 49ERS

Wide receiver Larry Fitzgerald will be listed as questionable for Sunday's game because of a bad hamstring, although Fitzgerald did practice fully Friday. The only Cardinal who did not practice fully -- and the only other Card listed as questionable -- is linebacker Kenny Demens (hamstring).

For the 49ers, WR Quinton Patton (foot) is out. Eight players are listed as questionable: CB Nnamdi Asomugha (knee), G Alex Boone (shoulder), T Anthony Davis (shoulder), C Jonathan Goodwin (illness), DT Ray McDonald (biceps), CB Carlos Rogers (knee), DT Justin Smith (shoulder) and LB Patrick Willis (groin).

WASHINGTON FINED

Linebacker Daryl Washington was fined $21,000 for roughing Carolina quarterback Cam Newton in last week's game.

WINNING, BUT WAITING FOR OFFENSIVE IMPROVEMENT

The winning record makes a difference – Fitzgerald said it was something to keep him "sane" for now – but offensively, the Cardinals are still looking for something much more productive than the past month.

"It feels good that we haven't played well by any stretch of the imagination on offense yet we are sitting here at 3-2," Fitzgerald said. "We control our destiny. The onus is on us. Simple as that. We are the phase that has to pick it up right now."

Arians said the Cardinals won't change their goals – six deep shots a game, a point for every minute of possession – but both he and quarterback Carson Palmer talked about making smarter decisions.

"Some of things we are doing, we should be able to execute well," wide receiver Andre Roberts said. "This week more than ever, I think we have simplified."