Following the entrance, a ceremony was held on the field to honor the Hall of Famer by retiring his No. 43 jersey.
As A's managing partner Lewis Wolff simply explained it during the ceremony, "We're here to honor one of the greatest pitchers in baseball history."
Nine of Eckersley's seasons were spent in Oakland, where he made the transition from starter to closer with unparalleled success. From 1988-92, he averaged 44 saves per season while helping the A's to four American League West titles, three AL pennants and a World Series championship in 1989.
His best season was in 1992, when he recorded 51 saves in 54 opportunities and posted a miniscule 1.91 ERA. For his staggering numbers, Eckersley was honored with both the AL Cy Young and Most Valuable Player awards.
"Those years were the best times of my life," said Eckersley, referring to his seasons spent as an A's player. "They were simply magic."
When he retired in 1998, Eckersley had recorded 390 saves, the second-most at that time and currently fourth on the all-time list. He also accumulated a record of 197-171 and a 3.50 ERA during a career that began with Cleveland in 1975 and included stops with the Red Sox, Cubs and Cardinals.
"He was as close to being automatic as any pitcher who has ever played," said former A's executive Wally Haas. "The game plan was to get the game to Eck.
"I have so much respect for the way that he played the game. It's a baseball cliché, but he played the game the right way and he never left anything on the field."
Former teammates of Eckersley agreed with Haas' thoughts.
"His biggest asset was his work ethic," said Terry Steinbach, who caught many of Eckersley's pitches while with the A's. "He showed the younger players what it takes to be that good. And he did it day in and day out."
"You knew the hitter had no chance," added retired outfielder Dave Henderson.
Eckersley was joined on the field for the ceremony by former teammates Rickey Henderson, Carney Lansford, Steinbach, Dave Henderson, Scott Sanderson, Rick Honeycutt, Mike Moore, Gene Nelson and Jim Corsi.
After the car parade entrance, the ceremony -- emceed by A's announcer Ray Fosse -- included a gift from the current A's team presented by rookie closer Huston Street, comments from current and former A's front office members and the unveiling of Eckersley's No. 43 jersey depicted on the right-field wall.
Following the unveiling, Eckersley stepped up to the mic.
"It was an honor for me to wear an Oakland A's uniform," he said between cheers and applause. "I'm here today to represent an era in Oakland A's history. The greatest moment was holding the ball in my hand for the last out of the 1989 World Series.
"As a kid from Fremont, this is the ultimate way for me to close my career. I leave for you a piece of me with the No. 43 and I leave with me a piece of Oakland forever in my heart."
Eckersley is the fourth Athletics player to have his number retired, joining Jim "Catfish" Hunter (No. 27), Rollie Fingers (34) and Reggie Jackson (9). In addition, the A's also honor the memory of former owner and managing partner Walter A. Haas, Jr. and Jackie Robinson on their outfield wall.
Fans who arrived early received a piece of memorabilia to go along with the memory of the ceremony. The first 10,000 through the gates were given an Eckersley replica jersey, courtesy of Wells Fargo Bank.
CJ Bowles is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.