Josh Reddick grew up with the Red Sox. He spent five seasons in the farm system, made his major league debut in 2009 and achieved almost every career first as a member of the Sox.

But he values nothing more than his time last season in Oakland with Jonny Gomes.

“He meant a ton for me,” said Reddick, now the Athletics’ right fielder. “I learned loads of stuff from him — on the field, off the field, clubhouse stuff, how to handle being somewhat of a leader in the clubhouse. I kept sucking in information as much as I could. I had a locker next to him all year, so I never had a dull moment. It was fun to be around him.”

With Gomes bringing life to the clubhouse and Reddick as his impressionable sidekick, the Athletics surprised everyone by winning the American League West last season. And although Reddick was sorry to see Gomes sign with the Red Sox in November, he hardly is surprised that the left fielder already is making a mark as a clubhouse leader here.

After the Marathon bombings, Gomes initiated the idea for the “Boston Strong” jersey that hangs in the Red Sox dugout. With help from his agent, he asked a bat company to inscribe the victims’ names — Martin Richard, Krystle Campbell, Lu Lingzi and Sean Collier — on the barrels of four bats, which he intended to auction to raise money for The One Fund Boston.

And it was Gomes who became the Sports Illustrated cover boy — and inspired a new Red Sox tradition — by flexing his biceps after hitting a crucial eighth-inning double April 20 in the first game at Fenway Park following the tragedy.

Indeed, Gomes’ impact on the Red Sox extends far beyond his .208 batting average in only 48 at-bats entering this weekend’s series in Texas.

“He just knows the right buttons to push,” Reddick said. “He kept us loose and on our toes whenever we were on a tough skid. When we had a winning streak, he was loud. When we had a losing streak, he was loud. He was Jonny being Jonny in the clubhouse, whether we were going really well or really bad.”

In a common sight last season, Gomes and Reddick would march around the Athletics clubhouse in matching yellow bathrobes. But Reddick’s fondest moment came when he was invited to Gomes’ hometown for a party to honor the Petaluma, Calif., team that advanced to the Little League World Series.

“That was a fun experience for me to go with him to Petaluma and do some stuff with those kids,” Reddick said. “To go through that with him, it was quite a blast. It made me a better ballplayer and a better person.”

Reddick was traded to Oakland in a December 2011 deal that brought two-time All-Star closer Andrew Bailey to the Red Sox. And when he hit 32 homers last season, it was easy to regard him as the “outfielder who got away.”

But Reddick has struggled this year, batting only .148 with a .260 on-base percentage, one homer and 13 RBI through Thursday. Meanwhile, his replacement, outfielder Daniel Nava, is off to a strong start for the Red Sox, batting .298 with a .396 on-base percentage, five homers and 18 RBI entering the weekend.

Reddick couldn’t be happier for his friend and perennially underestimated teammate in the minors. And he hopes Nava soon will become better known for his ability than for his unique backstory, including signing with the Red Sox for $1 out of the independent Golden Baseball League and working as the equipment manager for his college team after getting cut.