In an era when most free agents are looking for a multiyear deal, Piazza is not, and he has no regrets about it.
"I have really been blessed in this game," Piazza said. "At this time in my career, a two-year commitment [isn't for sure], I'm not young anymore.
"I just felt like it would be better for everybody involved. At this point in my career, I want to take it one year at a time. That's what happens when you mature and evolve."
The A's officially announced on Friday that Piazza is the newest member of the American League West champions with a one-year contract worth $8.5 million.
Piazza said he chose the A's because he wanted to play for a contender and that the decision was supported by his family. Another reason was the "flattering" of A's general manager Billy Beane.
"Billy from the start was very adamant on how I could contribute to the team," Piazza said during a conference call on Friday. "I am very happy to be a part of a great tradition of winning. This team has done a lot, and is not in one of the larger markets. In all, it is a great opportunity for me."
"I was really impressed with him," said Beane. "This is a guy that seemed like a perfect fit."
Piazza comes to the AL after spending his entire career in the National League as a catcher since 1992. He said he had "mixed emotions" about putting away his catching gear to be a designated hitter.
"I was always happy with the job I have done behind the plate," Piazza said. "I have always prided myself behind the plate. I am just going to try and be a complete hitter in the lineup."
Piazza said he still plans to sit in on the pitchers and catchers meetings and wants to catch during bullpen sessions.
Piazza batted .283 with 22 home runs and 68 RBIs in 126 games with San Diego last year, his 15th season in the Major Leagues. Those numbers came in 399 at-bats, and Beane feels those numbers could increase with Piazza being in the lineup on a day-to-day basis.
"We're anxious to see how he can do being out of the catcher position," said Beane, who thinks Piazza will likely be in the cleanup spot. "If anything, it will get him a lot more at-bats. It gives him a chance at 30 homers."
Piazza will have a tough task in replacing Frank Thomas, who departed to the Toronto Blue Jays. In 2006, Thomas hit .270 with 39 homers and 114 RBIs and propelled the A's offense to its first postseason since 2003.
Piazza is a .309 lifetime hitter with 419 homers, 1,291 RBIs and a .551 slugging percentage.
"He will have to fill some pretty big shoes with Frank," Beane said. "Mike is pretty accomplished in his own right. We thought [Piazza] was really important with Frank's departure. There is a very strong possibility that both of these guys will be in the Hall of Fame."
Beane said that the A's are still pursuing a young right-handed hitting outfielder to possibly replace free agent Jay Payton as the team's fourth outfielder. Payton led the A's in batting average (.296) in 2006, and Beane said the chances of re-signing Payton are "highly unlikely."
Ryan Quinn is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.