Instead of cleats on his feet, he wore ice skates.
"Seeing how far these people have to hit it to hit a home run, when you see Barry Bonds hit it over the wall, it's impossible," Foster said. "It's amazing to actually be on the field."
He isn't the only one getting a close-up look this holiday season. The Giants have installed a 60-foot by 120-foot ice rink atop the infield and opened it up to the public. It's believed to be the first time a Major League ballpark has doubled as a public ice rink.
The Giants, whose eight-year-old bayside ballpark has hosted a variety of nonbaseball events, are charging $20 for adults to skate, $15 for children and $5 just to watch. It's $40 for unlimited use between now and when the rink closes Dec. 9.
The whole thing serves as a promotion for the "Brian Boitano Skating Spectacular" that will be staged here Wednesday, starring Barry Manilow.
Music blares from the sound system and pairs of skates of all sizes line the wooden bench in the visitors' dugout. Adrienne Green was buying her tickets for the ice show when she saw a flier about skating.
"This is a very cool concept," said Green, who brought her two sons, ages 6 and 8. It was a sunny fall day; the boys didn't have school and were happy to be outside.
"They were wondering where the pitcher's mound went," Green said as U2's "Beautiful Day" played loudly in the background. "I thought that was a really good question to be asking."
Giants fan Jim Priestley attends about four games a year. He came with his wife and their two kids, and though Priestley opted not to skate himself, he was entertained watching his family and their friends form an ice train.
"I've never been here and touched the grass. It's neat," he said, reaching down to pick a clump. "The visitors' bathroom, it's terrible. That's probably good. You don't want them feeling too welcome."
Frank Bennett, a longtime competitive skater who lives in San Francisco and is serving as coach and greeter at the rink, taught Nicole Priestley and friend Lauren Foster how to twirl, sans skates.
"It's so nice out here. It's like a little paradise," said Lauren's mom, Shannon Foster.
As the ice became bumpy and began to melt in the afternoon sun, this reporter turned to dodge Justin -- in his red turtleneck and matching khaki pompom hat with red stripes -- and wound up pulling a headfirst slide that would later yield two purple knees and a bruised left hip.
It was a move the major league coaches would rarely advise.
"That's a slide into second base right there," the boy said with a smile.
Chalk it up to part of the experience.