"I'll help him with anything he needs," Kotsay said. "We'll be on pretty different schedules, because he's a pitcher and I'm a position player, but I can definitely help him with all the stuff that can be a distraction when you get up here for the first time."
Stuff like knowing how much to tip the visiting clubhouse manager, one of the mysteries Williams helped Haren solve.
"It doesn't sound like much," Haren said, "but it's huge for a rookie to have a veteran kind of show you the ropes."
"There's a lot of little things you need to get a handle on," Kotsay said. "How to get to the ballpark, what time to get there, where to eat, tipping ... that's all part of it."
One goal Kotsay has is to make sure Windsor doesn't challenge the unofficial A's rookie record for first-day fines, set by Nick Swisher when he was called up to meet the team in Toronto late in the 2004 season.
Among the offenses for which Swisher was dinged a total of $1,100 was taking the team bus to the ballpark.
"That's a no-no for most guys," Kotsay explained. "Everybody's got a lot of work to do before the game, and the bus gets to the park pretty late, so the only guys who take it are relievers, who can get their conditioning in during batting practice, or guys who know they have the day off to clear their head."
More on Windsor: A 6-foot-2, 235-pound righty who was a third-round pick in the 2004 First-Year Player Draft, Windsor is 8-0 with a 4.07 ERA for Triple-A Sacramento and was a combined 12-1 at Sacramento and Double-A Midland.
Outfielder Milton Bradley and reliever Justin Duchscherer are among the A's who have recently spent time with Sacramento while rehabbing, but neither of them saw Windsor pitch. Lefty reliever Ron Flores, however, was Windsor's teammate for about a month.
"He's got good [stuff]," Flores said. "He's not the hardest thrower in the world, but he's got a great changeup that people just swing right through. He's a big guy, kind of your typical big-school pitcher. You can tell he's pitches in a lot of big games, because he's not scared out there at all."
Ironically, Flores and Windsor might not be teammates again in the big leagues. The A's will need to clear roster space for Windsor, and Flores is expected to be the odd man out.
Oakland manager Ken Macha said Windsor's performances will dictate how long he stays on the roster and how often he pitches. The A's have eight of the next nine Thursdays off, so Windsor might be a once-a-week guy, initially.
Macha added that the move, which was being considered before the All-Star break, will strengthen the bullpen by returning Kirk Saarloos, who picked up a save on Thursday and pitched two hitless innings on Friday, to a full-time relief role.
"We're trying to continue to get the 'pen back to where it was coming out of Spring Training," Macha said.
The A's also are hoping that Windsor can provide the kind of midseason rotation boost that Tim Hudson and Rich Harden gave the club when they were called up.
Dribblers: Antonio Perez got another start at third base on Saturday, marking the first time this season he's started three consecutive games. Prior to making an error in the seventh inning on Saturday, Perez had been flawless at the hot corner since taking over for Eric Chavez, prompting Macha to praise the work of infield coach Ron Washington. ... Macha, who left Friday's game with a broken blood vessel in his nose and was treated during the game at a local hospital, said he handed the managing duties over to first-base coach Rene Lachemann rather than bench coach Bob Geren, based on Lachemann's eight years of big-league experience as a manager. Geren took over for Lachemann at first base, something Macha said he did once while serving as bench coach for former A's manager Art Howe. ... Righty Shane Komine, 25, won his fourth consecutive start for the River Cats on Friday to improve to 7-7 overall, throwing 5 2/3 innings while combining with four relievers on a shutout of the Salt Lake Bees. ... One of the relievers was A's righty Jay Witasick, who is on the DL with ankle tendinitis. Witasick, who threw 17 pitches and gave up a hit and a walk in one inning of work, will throw roughly 30 pitches on Monday for Sacramento but isn't expected to return to the big leagues for at least another week. ... Sacramento outfielder Hiram Bocachica, the likely candidate for promotion should the A's disable Chavez, went 2-for-4 with two RBIs to raise his team-leading batting average to .344.
Coming up: A's righty Joe Blanton (8-8, 4.95) takes on Red Sox righty Kyle Snyder (1-0, 10.29) in the series finale on Sunday at Fenway Park. The first pitch is set for 11:05 a.m. PT.