[1] Hudson made his MLB debut on June 8, 1999, in which he allowed three runs in five innings as the A's lost to the San Diego Padres 5–3.
[2] Zito made his MLB debut on July 22, 2000, in which he allowed just one run in five innings in a victory over the Anaheim Angels, thus marking the beginning of the "Big Three" era.
[15] The Big Three were able to lift the A's to an AL West Division title in 2003, earning them their fourth consecutive postseason appearance.
Hudson began the postseason by going 6.2 innings and allowing three runs in Game 1 of the 2003 ALDS, as the A's defeated the Boston Red Sox 5–4.
[16] Zito had a strong outing for the A's in Game 2 of the ALDS giving up only one run in seven innings to lead the A's to a 5–1 win over the Red Sox and putting them ahead 2–0.
[18] The following year, Hudson's season was cut short due to an injury that would prove to be costly for the A's as they finished second in the AL West and missed the playoffs for the first time since 1999.
After the 2004 season, A's general manager Billy Beane traded Tim Hudson to the Atlanta Braves and Mark Mulder to the St. Louis Cardinals, breaking up the Big Three.
Mulder spent four seasons with the Cardinals, after which he was released after suffering from rotator cuff and other shoulder problems during his tenure there.
Those injuries prevented Mulder from appearing in the Cardinals' 2006 postseason run, culminating in the team's World Series championship.
In the 2006 season, Zito finished with a 16–10 record, 3.83 ERA, and 151 strikeouts to help lead the A's to an AL West title.
After taking a year off from baseball in 2014, Zito spent one last season with the Oakland A's' Triple-A Affiliate, the Nashville Sounds.
This call-up, combined with a series against the Giants with a scheduled start by Hudson, set up an impromptu reunion of the Big Three.
With Mulder in attendance, Zito started for the A's against Tim Hudson of the Giants in front of a sold-out crowd at Oakland Coliseum on September 26, 2015 - nearly 11 seasons after they last played together on the A's.