ARLINGTON -- Mike Piazza wasn't among the A's crowded around the clubhouse television Tuesday when Barry Bonds hit his 756th career home run to pass Hank Aaron, but he's as qualified as anyone in an Oakland uniform to put Bonds' accomplishment in perspective.

Piazza, 38, is the oldest member of the A's, has the most big-league service time (15 years), and has more home runs as a catcher (396) than anyone in history and 422 homers overall.

"It's an amazing accomplishment," Piazza said Wednesday before the finale of a three-game series at Rangers Ballpark. "Aside from it being an incredible number of home runs, it's the number of years you have to stick around and still play at that high of a level. And when you're a home run hitter, hitting a home run is the one thing that pitchers are trying to not let you do, but he keeps doing it.

"Take it from me, it's not easy."

Piazza also lauded Bonds' power of concentration, his ability to block out distractions.

"It's difficult to play this game even when there's not a lot of pressure on you," he explained, "but since he started getting close to 700, he's been under constant pressure. And I'm not even talking about the controversy. I'm talking about the expectations put on him, all the media and everything. It's incredible."

A's manager Bob Geren played against Bonds in 1993, when Geren hit three homers with the Padres and Bonds hit 46 to win National League MVP honors in his first season with the Giants. Geren said Bonds and Ken Griffey Jr. were considered the best players in the game then, and his appreciation for Bonds' talent has only increased.

"The two most impressive things to me about the record are [that he still broke it despite] the number of walks he's gotten and that ballpark," Geren said, referring to Bonds' 2,500-plus career free passes and spacious AT&T Park. "That's not really a home run ballpark. You see him lean back, hit it to dead center and know it's gone, it gives you the illusion of it being easy to hit the ball out of there. But those are not easy fences to reach.

"He makes that big park look small, and it's not."

Second baseman Mark Ellis also mentioned the size of AT&T Park and Bonds' focus and longevity when asked what impresses him most about the home run mark.

"People outside of baseball probably don't realize what a tough park to hit in that is, but it's one of the tougher places to hit a home run," Ellis said. "The scrutiny he's been under has been incredible, too, and he's been playing, what? Twenty-two years? I've played six years, and I can't even fathom 22. That's incredible.

"Just having a chance to play against him is something special."

Back issues: Third baseman Eric Chavez isn't the only Athletic with back issues. Center fielder Mark Kotsay, who had back surgery in March and didn't make his 2007 debut until June 1, missed his fourth consecutive start Wednesday.

"He dove for a ball [Saturday], and he's been a little stiff with his back," Geren said. "He's OK today. He feels fine, and I'm confident he'll be available tonight if we need him and be ready to go Friday."

Kotsay has struggled against left-handed pitching this season, and the Rangers started lefties in the first two games of the series.

"We've got an offday [Thursday], so I'm sure he'll be fine for Detroit."

As Geren was holding his daily press briefing, Chavez was having his bad back examined by a specialist in Arlington. Depending on what the specialist tells Chavez, he might fly from Texas to Southern California for another opinion.

After the game, Chavez said he was told he had a bulging disk and was advised against any baseball activities for two weeks before being re-evaluated.

Dribblers: Wednesday marked the end of stretch of 20 consecutive days with a game for the A's, who open another 20-day stretch Friday. ... The A's will not adjust their rotation as a result of the off-day, instead giving each starter an extra day of rest. ... Backup catcher Rob Bowen got his fifth start of the season. ... Triple-A lefty Dan Meyer have up two runs on three hits and a walk while striking out seven over 5 1/3 innings on Tuesday but did not get the decision in the River Cats' 7-3 loss to Oklahoma. Meyer is 6-2 with a 3.40 ERA in 19 starts this season.

Up next: A's righty Joe Blanton (9-8, 3.71 ERA) takes on Tigers righty Jordan Tata 1-1, 3.75 ERA) on Friday in the opener of a four-game series at Comerica Park. The first pitch is set for 4:05 p.m. PT.