Fontenot and Theriot made up the middle-infield tandem for LSU when they won the College World Series in 2000. They then went on to be teammates with the Cubs from 2005 to 2010.
The last couple of seasons, they've gotten to play against one another, as they are during this weekend's series between the two clubs at Citizens Bank Park.
"It was pretty fun when we got a chance to play together after college with the Cubs and everything," Fontenot said. "But it's always fun to play against former teammates."
The duo was actually together once again this past Spring Training with San Francisco, but Fontenot was released in late March. The Phillies signed him a few weeks later.
Fontenot said he and Theriot had talked since the Giants arrived in town for this weekend's three-game set but had not yet had the chance to hang out.
"We keep in touch whenever we can," Fontenot said. "Schedules get kind of crazy sometimes, especially in the offseason, seeing family. We stay in contact pretty well and try to get together when we can."