Dallas running back Julius Jones slammed his helmet into the middle of the line, ran into all 324 pounds of Marcus Tubbs and didn't gain an inch.

And in that same first-quarter drive, Tubbs looped from right to left and planted Cowboys quarterback Drew Bledsoe into the FieldTurf for a 7-yard sack. A play later he stuffed Jones again for a 2-yard gain on second-and-17.

This is what the Seahawks have been talking about since draft day 2004. This is the agile athleticism they've promised from this mammoth man. This was the potential slowly unveiling itself.

In this second exhibition game of the long, long season, Tubbs was one of the leaders of a revamped defense. In less than three quarters last night, he had three tackles, one assist and a shared sack with his new mentor, Chuck Darby.

It looked like some kind of pigskin prologue to the 2005 season.

Last year was the worst of Tubbs' young life. His heart and his attentions were split between Seattle and DeSoto, Texas, where his mother Jeanette was seriously ill. This summer, Tubbs looks more comfortable in his body and more comfortable at defensive tackle.

"To be able to come into training camp and come in focused and have a clear mind and not have to deal with issues of family back home and getting my contract done and the injuries that occurred along the way has helped me out on the field," Tubbs said after a dreary 18-10 loss to Dallas. "I can see where it's going to pay off.

"I have so far to go, I mean so far to go, but I can already see where it's paying off a little bit. I need to improve on consistency with my technique. I have to keep my pads down on every play. Have to be a better student of the game and break my opponents down better. It's going to take time."

His first season never got out of neutral. All year Tubbs was stuck between coming and going, his attention divided between learning his profession and concerns about his mother.

The Hawks' first-round pick was caught between the unbridled joy of realizing his professional dream and the profound sadness of knowing his mom, who had been his foundation for his first 23 years, was losing her fight with cancer.

And when he finally worked his way into shape and into the starting lineup, Tubbs suffered an ankle injury in the Monday night game with Dallas that ended his season. Two days after his injury, his mother died.

"Last year was pretty rough," Tubbs said. "When I was trying to get my contract done I was home with my mom the whole two weeks, but during the season I wasn't able to go home and see her, and that killed me inside.

"But my mom knew this was my job and she gave me her blessing and told me to stay out here and do the best I could out here. But overall it was, by far, the toughest time in my life."

Through his hardships, Tubbs has leaned on his father Mack for support.

"I talk to my dad every day," he said. "He's my best friend. He's my brother. He's everything to me, and we've definitely needed each other through these tough times."

Coach Mike Holmgren defended his rookie against the critics last season. Kept positive about his potential. Kept talking up about his future.

Now the future has arrived.

Their soft schedule and their lethal offense make the Seahawks the favorites in the NFC West — if quarterback Matt Hasselbeck stays healthy — but their defense still has some explaining to do.

We've been fooled before.

Last season, the defense was ranked best in the league after three weeks. It finished 26th. Last season, the Hawks blew a 17-point fourth-quarter lead and lost at home to St. Louis and allowed 24 points in the second half of another home loss to Dallas.

For all of the dropped passes that killed drives, it was the defense's collective loss of confidence and its inability to stop teams in the fourth quarter of close games that left another Seahawks season lolling in disappointment.

Tubbs has to be part of the solution. He is lighter this summer. More active. Better educated.

"I feel the sky's the limit for me," Tubbs said. "I try to approach every game not really worrying about press and accolades. I pray before every game, and all I ask is to never cut myself short. That's what I try to take into every practice, every game. And I see good things coming out of this."

A season later than he had hoped, Tubbs looks ready to make a difference.

Steve Kelley: 206-464-2176 or skelley@seattletimes.com