"He'll tell me to keep my head up, but make sure that I take care of the ball," he said. "That's what a running back has to do."

Fumbling is a rare offense by Jackson, but he lost two in the third quarter Sunday that contributed to Arizona's NFC West-clinching 34-10 victory.

Trailing 20-7, the Rams were driving to make it a one-score deficit when Jackson coughed up the ball, with linebacker Karlos Dansby recovering at the Cardinals' 22-yard line. On the Rams' next series, defensive tackle Darnell Dockett scooped up another Jackson bobble and ran 11 yards for a touchdown that made it 27-7.

Linebacker Gerald Hayes, who forced both fumbles, said, "When I looked back and saw Dockett was going to score, it was like a sigh of relief. You make one play and then it turns into an even bigger play."

Playing on an improving right leg, Jackson rolled up 48 yards on eight carries in the first half at University of Phoenix Stadium. "I was really excited coming into the game, knowing that the leg was starting to feel really good," said Jackson, who had come back the previous week after missing four games and most of a fifth with a strained thigh muscle.

"Steven's a monster," said Adam Goldberg, who started at right tackle. "It's an honor to block for him, because you know that he'll pound out the tough yards and he'll work just as hard and play just as physically as you do up front."

The Cardinals are 10th in the NFL in total defense, and Jackson rarely had much room to operate. "I knew it was going to be a tough game," he said. "They have a defense that's really physical."

In addition to a strong and active front seven, the Big Red secondary is stout against the run, Jackson pointed out. "Their corners do a good job of keeping containment and forcing the run to stay within the tackles," he said. "And their linebackers and their safeties do a good job with gap protections."

Jackson finished with 64 yards on 19 carries.

Quarterback Marc Bulger has been sacked just once in the last two games, and it's no coincidence, wide receiver Dane Looker stressed.

Jackson's presence "poses a threat for the defense," Looker said. "They really have to make sure that they stop the run. ... A good running game opens up everything else in the offense."

With the Rams down 20 points after three quarters, Jackson's impact was lessened in the fourth: 20 of the Rams' final 24 snaps were pass plays.

"He made some incredible runs early on," Bulger said. "And then, again, you get behind and you kind of take him out of the game because you've got to start throwing the ball."

The two lost fumbles played a big role in forcing the Rams into that untenable situation, Jackson acknowledged.

"I was trying to make things happen. But that's still Football 101 for running backs: protect the ball," he said. "I was fighting for extra yards and the ball slipped out. There's really no excuse."

Steve Jackson, a retired Marine who served in Vietnam, is a source of "wisdom and knowledge," his son said. "When times are really tough like this, I have a tendency to get really down. Sometimes I just need that fatherly advice. He'll point the good things out, and he'll definitely point the bad things out. ...

"He keeps it honest with me, but he makes sure that I don't let it affect the rest of my play."