Lynn found it difficult to duplicate the extraordinary success of his first season, and was hampered by injuries. These sometimes were caused by fearless play, such as a broken rib from crashing into an outfield wall, or knee injuries from breaking up double plays, but most were simply of the nagging variety, such as strains and sprains. Lynn won three more Gold Gloves in 1978-80 and finished fourth in the 1979 MVP voting, while being elected to the All-Star team every year with the Red Sox.
Following the 1984 season, Lynn signed with the Orioles, who signed numerous free agents in the mid-1980s in an ultimately unsuccessful effort to win another World Series after their 1983 title. Lynn never played more than 150 games in a season and only topped 140 games four times. From 1982-1988, his home run totals were 21-22-23-23-23-23-25. His four consecutive years with exactly 23 home runs tied Ken Boyer (24 each year for Cardinals from 1961–1964) for most consecutive years with exactly the same number of home runs (based on 20 or more home runs); Adam Dunn later matched this mark with 40 each year from 2005-2008.
Detroit acquired Lynn for their 1988 pennant drive, which also proved unsuccessful. There was some initial controversy with this trade; though the trade was made on the day of the trading deadline, while Lynn was en route to Detroit, he was technically not in "Detroit airspace" when the deadline passed, so he was ruled ineligible for the postseason. MLB Commissioner Fay Vincent later overruled this decision, declaring that as long as the transaction was completed by the deadline, the player need not physically be in the new team's city to be eligible to play in the playoffs. Following a disappointing 1989 season, Lynn ended his career with one season in San Diego (1990), retiring at the age of 38.
Lynn has raised over $17,500 through charity work, primarily for Child Haven and The FACE Foundation, a home for abused and neglected kids.
Lynn recorded a hit on the first pitch off Lee Smith for the All-Star Legends softball game in St. Louis (2009). Both appeared in the 1983 All-Star Game as opponents. Lynn also hit a home run in the 2010 All-Star Legends softball game in Anaheim.
Lynn worked as a baseball color analyst for ESPN from 1991–98, doing some College World Series games and some West Coast MLB games. He has also been a spokesman for Gillette and MasterCard, and occasionally entertains clients at Red Sox games from the Legends Skybox at Fenway Park.
^During his lengthy major league career, Lynn played for five different teams, but considers himself a member of the Red Sox family. “I’m a Red Sock. I didn’t want to leave the Red Sox,” said Lynn, who was traded to the California Angels in January 1981. “I came up with them and from 1973 to 1980 I was their property. I thought I’d end up spending my entire career in Boston. It was tough, even though I was going to a great team and playing for a great owner in Gene Autry.”
^Los Angeles Times, August 19, 2012, page C5, "Fred Lynn's Cautionary Tale"