Over 12 NHL seasons, McDonald accumulated 182 goals and 307 assists for 489 points in 685 regular-season games with Anaheim and St. Louis.
McDonald has been riddled with concussion problems over his career, though, which is the reason he's hanging up his skates.
"The last few years, too much of the focus became worrying about the next hit. I was always thinking about it," McDonald told truehockey.com.
McDonald, who won the Stanley Cup with the Ducks in 2007, was set to become an unrestricted free agent this July.