And retaining free-agent outfielder Jay Payton is no slam dunk, so Oakland could very well have to replace their 2006 batting leader, too.
In other words, it's business as usual for the ever-changing A's, who, fresh off winning the American League West and making their first appearance in the AL Championship Series since 1992, will head to the annual Winter Meetings in Orlando, Fla., with a typically lengthy to-do list.
"It's different every year in terms of the needs you want to address," assistant general manager David Forst said. "But it's the same in a sense because there are always needs."
Oakland's relatively modest payroll requires the club to retool virtually every offseason, but this year the needs are particularly significant.
Thomas, who hit 39 homers and drove in 114 runs, was the team's offensive MVP. Payton, who batted .296 and started at least 40 games at all three outfield positions, wasn't far behind. And Zito had the lowest ERA (3.83) among A's starters while tying for the team lead in wins (16).
So as GM Billy Beane, Forst and the rest of Oakland's personnel brain trust sets up camp in an Orlando hotel suite, they'll do so with a fairly specific plan. They're not saying what the plan is, but the club has been in contact with the agents for several potential replacements for Thomas, including Barry Bonds and perhaps Cliff Floyd.
Mike Piazza, whom the A's considered before signing Thomas last winter, also is a possibility.
"We've talked about a lot of players internally," said Forst, who added that the A's aren't necessarily looking for someone capable of carrying the offense the way Thomas often did in the second half of the season.
"There's some good players already here."
Whether one of them will be Payton remains to be seen. Payton, 34, said late in the season that he's open to a return, but he made $4 million in 2006 and likely will command more than that in 2007.
The A's, whose 2006 payroll was between $65-68 million, have roughly $32.5 million of their 2007 payroll already committed to third baseman Eric Chavez ($9.5 million), center fielder Mark Kotsay ($8 million), righty Esteban Loaiza ($7 million) and catcher Jason Kendall ($13 million minus $5 million from Pittsburgh).
"I don't know what's going to happen," Payton said during the ALCS. "This is a great group of guys and a great organization, but I've been around long enough to know that this is a business, and they have business decisions to make. I'm one of them."
Forst conceded that the big money being thrown around early in the Hot Stove season suggests that re-signing Payton might be difficult, but didn't rule the A's out of the running.
"We've stayed in touch," Forst said. "We check in with his agent on a fairly regular basis. ... As is always the case with free agents, it's going to be their decision as much as it is ours."
Should Payton leave, the A's could move Nick Swisher, who split time at first base and in left field last season, back to the outfield full-time and hand the first-base job back to Dan Johnson. Johnson, an All-Rookie selection in 2005, struggled early in his sophomore season and spent part of it in the Minors.
But Johnson's future with Oakland is far from secure. Beane has said he might look outside the organization for a starter to replace Zito, and because Oakland's top hitting prospect, Daric Barton, is a first baseman, Johnson could be among the players dangled as trade bait.
Barton, 21, batted .316 at Double-A Midland in 2005 and had his 2006 season at Triple-A Sacramento interrupted by an elbow fracture. Does Barton have a shot at making the big-league club this spring?
"Yes," Forst said.
Mychael Urban is a national writer for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.