STANFORD, Calif. — Every time Tyler Gaffney attended a Stanford practice last year, coach David Shaw teased his former running back that he had one year of eligibility remaining.

Shaw never really thought Gaffney would put off a professional baseball career and return to football anytime soon, not with him playing so well in the minors for the Pittsburgh Pirates. For the most part, he just joked with him about the possibility.

"I'd walk up, and I used to run the wildcat, he'd yell out, 'Tiger Gaff!' I'm in jeans and walking up there. Everyone would laugh," Gaffney said. "Little things like that, saying, 'Oh, we'll see you next year.' Coach would come up and give me his business card and say, 'Oh, we'll talk later. We'll talk later.' "

What Shaw found out later is that Gaffney already had been plotting a return.

After a solid debut with the short season Class-A State College Spikes, Gaffney got the urge to resume his football career and chase the two things missing from his Stanford resume: a degree and a championship.

He wrote out the pros and cons of the decision on a whiteboard with his parents in January. Then, he called a meeting with Shaw to make sure Stanford would welcome him back. Finally, he parted ways with the Pirates — at least for now — to make a run at a Pac-12 Conference title and a national championship with the fourth-ranked Cardinal this fall.

Gaffney said he missed the adrenaline on football game days, the challenge of "moving another man against his will" and lining up with 10 other players as opposed to a one-on-one matchup with a pitcher. At times, he said living with a host family in State College, Pa., and being surrounded by intense Penn State football fans felt like being on another planet compared to Stanford's serene Silicon Valley campus.

When baseball season ended, Gaffney attended almost every Stanford home game and a couple on the road, including at Oregon when the Cardinal outlasted the top-ranked Ducks in overtime en route to a conference championship and the program's first Rose Bowl victory in 41 years.

Watching from the sideline and the stands reminded him what he had left behind.

"I wish everybody could take a year off and be a fan for a game just to see what's going on from the outside," Gaffney said. "It's just an unbelievable experience to be so helpless."

Ever since he could remember, Gaffney played more than one sport. He starred at San Diego's Cathedral Catholic High School in baseball and football and chose Stanford because of the opportunity to play both, following in the footsteps of Cardinal greats such as John Elway and John Lynch and Toby Gerhart.

In the back of his mind, Gaffney always knew he could come back to football.

NCAA rules allow an athlete to play professionally in one sport and maintain eligibility in another, so long as they don't receive money from endorsements. While it's rare for a player to return after missing an entire season of major college football, plenty of players have rotated between sports, including at Stanford.

Elway (Yankees) and Lynch (Marlins) played in the minors before going back to Stanford. Gerhart, the 2009 Heisman Trophy runner-up and current Minnesota Vikings running back, turned down an opportunity to play professional baseball. More recently, Seattle Seahawks quarterback Russell Wilson left North Carolina State for a summer in the Colorado Rockies' farm system before enrolling at Wisconsin for a sensational senior season.

Gaffney's return couldn't come at a better time on The Farm. With Stanford career rushing leader Stepfan Taylor playing for the Arizona Cardinals now, Gaffney will get more opportunities than he ever had before.

In his first three seasons, Gaffney ran for 791 yards and 12 touchdowns on only 156 carries. He also caught 17 passes for 187 yards and three TDs.

Shaw said he always knew Gaffney could come back. He just thought Gaffney would play at least two years of baseball first.

"When it's all said and done, he's going to play football for pay in the future," Shaw said.

Senior Anthony Wilkerson and Gaffney, who played ahead of Wilkerson two years ago, will likely receive the majority of snaps. But Ricky Seale, Kelsey Young, Remound Wright and Barry Sanders all will receive carries on what has been one of the nation's best rushing teams since Shaw and his predecessor, Jim Harbaugh, arrived in 2007.

And Gaffney embodies that tough, physical style. He rarely runs out of bounds, preferring to go head-on with defenders — a mentality that often surfaced on the baseball diamond, too.

Gaffney, drafted in the 24th round by the Pirates as an outfielder, batted .297 and had an impressive .483 on-base percentage for State College thanks to a style that makes advanced statisticians salivate: He drew 20 walks to 20 strikeouts and was hit by a pitch an unbelievable 20 times in 38 games.

"I swear I don't stand on the plate. I don't shy away from the ball," he said.

Gaffney, who said he has 20-15 vision, surmised that part of the reason he gets hit so much is his mental approach at the plate. He is double-majoring in sociology and psychology, and he loves using methods he has learned in the classroom on the field.

In typical Gaffney fashion, he said his favorite moment from last season was a benches-clearing altercation, which started when Connecticut Tigers pitcher Angel Nesbitt threw behind Gaffney. Gaffney smiled and stood closer to the plate, getting plunked in the left shoulder on the next pitch. The umpire ejected Nesbitt.

"Smiling goes a long a way," Gaffney said. "I like pressing people's buttons."

Gaffney never charged the mound; he said he couldn't afford a fine. He learned in his first game as a professional that contact in baseball can come at a price.

Gaffney stole 11 bases for State College, and on his first attempt, he started to slide head-first into second. At the last moment, he remembered the Pirates fine minor-league players $150 for going in head-first, and he jammed his left pinkie finger in the dirt trying to make the transition. The knuckle on his left pinkie is still misshaped.

"You could always tell the way he plays that he's a football player first," Wilkerson said.

Even with that scar, Gaffney said one of the reasons he jumped at the chance to play professional baseball is because football players typically don't have long careers.

"I think getting hit by the ball is a little easier than getting hit by Shayne [Skov]," he said, referring to Stanford's star linebacker.

Gaffney hasn't stepped in a baseball cage since earlier this summer and said he'll resist any impulse during football season. But he'll likely return to the sport at some point.

The Pirates retain Gaffney's contract rights the next four years. He said the organization was surprised by his decision to leave because "they saw me trying to move up and do better. It'd be one thing if I was failing and it was like, 'Oh, he's going back to football.' They said, 'Pass a physical, and we'll welcome you back.'"

Gaffney said he always admired two-sport stars such as Deion Sanders and Bo Jackson. But when he left Stanford and the Pirates, he said both times "I was ready at that point to do one thing."

In a perfect world, Gaffney would play both sports professionally. And as far-fetched as that might sound, pursuing that dream remains his goal.

"It's a little harder than it used to be," Gaffney said. "But I'd rather try and be told, 'No,' than not try at all and always wonder."