UPDATE: The pitching matchup between Zito and Hudson will occur this weekend.

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On Wednesday the Oakland Athletics announced they have called up former big-league starter Barry Zito. The 37-year-old was signed to a minor-league contract before the season and general manager Billy Beane said Zito would not be called up this year. However, injuries have forced the A's to promote him.

The latest rumors indicate the Athletics and San Francisco Giants could be working on a Zito vs. Tim Hudson pitching matchup towards the end of the season to honor the veterans. Hudson plants to retire after 2015 and Zito's career could also be coming to an end soon. He took all of 2014 off and has played in the minors for all of 2015.

"This is likely an MLB farewell for Zito," writes Mike Oz of Yahoo! Sports. "The A's - with their shared history and his popularity in the Bay Area - offered Zito the best chance to return to the big leagues. It would be a surprise if he tried again next season."

The two pitchers were former teammates on the historic "Moneyball" Oakland A's team of the early 2000s.

The injury to A's pitcher Jesse Chavez opened the door for this potential scenario. The right-hander was found to have suffered a non-displaced fracture in his ribs after going in for an MRI due to rib soreness. It's unknown how he suffered the injury, but he'll join fellow pitchers Kendall Graveman, Jesse Hahn, Jarrod Parker and Chris Bassitt on the DL.

FOX Sports' Ken Rosenthal reported earlier today that the Athletics "will try to figure out how to make a start against [Tim] Hudson happen," but ESPN Insider Buster Olney can be credited with fueling the initial speculation.

"In a meaningless game at the end of a long season, it would be fun -- for the A's fans, for Zito, for Hudson -- and would be a way of honoring both pitchers for the pivotal roles they played for one of the better teams we've seen in the past quarter-century," Olney wrote last week.

"Promote Zito for one day and give him the ball, for the final appearance of his career, and let him pitch against Hudson, an old friend and teammate, in what could be the last game of Hudson's career. Athletics manager Bob Melvin and Giants manager Bruce Bochy could have a gentlemen's agreement to set aside the designated hitter for a day and let Hudson and Zito face each other, for one last bit of bragging rights."

And why not? Both teams are all but officially out of the playoff race. The A's are one of the worst clubs in the American League while the Giants trail the Dodgers by 7.5 games in the NL West and the Cubs by 7.5 games in the NL wild-card race.

Zito, a former AL Cy Young winner, has played 14 MLB seasons with the Athletics and Giants. The left-hander went 102-63 with a 3.55 ERA in 222 career starts with Oakland before signing a massive seven-year, $126 million deal with the Giants. Unfortunately, he never lived up to that contract and finished his career in San Francisco with a 63-80 record and 4.62 ERA in 208 games (197 starts) from 2007-2013.

Hudson, 40, is in his 17th MLB season and will hang up his cleats after 2015. The right-hander is 221-132 with a 3.49 ERA in 479 career games (476 starts) with the Athletics, Giants and Atlanta Braves.

The two veteran pitches both won World Series titles with the Giants.