Gio Gonzalez. (AP Photo/Alex Brandon)

Before Friday’s series-opening game against Oakland, the first meeting between the Athletics and Nationals since 2005, Gio Gonzalez emerged from the visitor’s dugout at Coliseum for the first time. “Sitting on the other side was kinda weird,” he said. In his first trip back to Oakland since he was traded to Washington in December 2011, Gonzalez hugged every member of the grounds crew preparing the field for batting practice. Gonzalez spent his formative professional baseball years with the Athletics, pitched for them for four seasons and earned his first all-star selection in 2011.

“I saw some former teammates,” Gonzalez said later. “Saw some ground crew guys, clubbies, security guards. I basically talk to anybody. Even guys in the parking lot. It’s a pretty cool feeling when guys still remember you. It was fun when I was here.”

Gonzalez isn’t the only Nationals player with deep ties to Oakland, and vice versa. The two team’s rosters are a web of connections as they have made eight trades over the past four years. Left-handed reliever Jerry Blevins, traded from Oakland to Washington for outfield prospect Billy Burns this offseason, was walking to the weight room earlier and ran into former teammates Sean Doolittle and Josh Donaldson. Blevins found his way around the bowels of Coliseum but it wasn’t easy.

“It’s different,” Blevins said. “Everything is backwards. In here, because of every tunnel splits, I’m used to taking a left instead of a right. Vice versa. I think this side, this clubhouse, is nicer. I really do. It’s the same setup but just newer stuff because of the sewage back-up.”

During batting practice, former Nationals reliever Fernando Abad, traded away this winter, hugged his former teammates. Former Nationals prospect Derek Norris is starting behind the plate on Friday for the Athletics and catching another former Washington prospect, left-handed starter Tommy Milone. Nationals outfielder Scott Hairston also spent part of 2009 with the Athletics.

Gonzalez is scheduled to start on Sunday and face some of his former teammates, but some of them are already on other teams by now. The experience will be fresher for Blevins, who spent parts of seven seasons with Oakland. Friday’s lineup has four left-handed batters and Blevins may be called upon to face his friends.

“We’ll see,” Blevins said. “I haven’t done it yet. Baseball is the easiest part. Baseball takes care of itself. That’s what we’ve been preparing ourselves for my 30 years of living. Once you get between the lines, that stuff kind of takes care of itself. The pregame stuff, seeing old familiar faces, in different colors.”