Mickelson's agents at Gaylord Sports Management made the announcement Wednesday, saying Amy Mickelson will likely have surgery in the next couple of weeks.
Mickelson, the world's second-ranked golfer, won his first title as a pro at Torrey Pines in early 1993. Since then he has won three major championships and a total of 36 events on the PGA tour.
Mickelson met his wife in college at Arizona State and married in 1996. The couple have three children: Amanda, 9, Sophia, 7, and Evan, 6.