For the most part, MLB MVPs have been players that have gone on to have outstanding careers. Many of them are Hall of Famers, while others were All-Stars many times in their careers.
However, there are some players that have taken home MVP awards when no one expected them to. These players had great seasons, but the rest of their careers were just decent at best.
Winning an MVP award is usually a good indicator of how a player's career will go, but that was not necessarily the case with the following players.
It is certainly debatable whether Bob O'Farrell deserved to win the National League MVP award in 1926. He hit .293 with seven home runs and 68 RBI. That same year, Hack Wilson batted .321 with 21 home runs and 109 RBI, while Ray Kremer went 20-6 with a 2.61 ERA. These two players probably deserved the award more.
While O'Farrell lasted 21 season in the majors, he was nothing more than an average player, ending his career with an OPS+ of 98.
For two consecutive years in the early 1990s, Terry Pendleton put up outstanding numbers. He led the National League in hits and batting average while also hitting for power. Pendleton earned his NL MVP award in 1991.
Outside of the 1991 and 1992 seasons and his rookie year, Pendleton was never an outstanding player. He had a 92 OPS+ for his career and hit .270 with 140 home runs in 15 seasons.
Al Simmons and Henry Heilmann dominated the American League during the 1925 season, but neither of them received the American League MVP award. Roger Peckinpaugh, who batted .294 with four home runs and 64 RBI, took home the hardware instead.
Peckinpaugh had a 91 OPS+ that year, nowhere close to Simmons (149) and Heilmann (161).
He was not much better over the course of his career, hitting .259 with an 87 OPS+, but he was a defensive wizard who posted a 25.0 dWAR (h/t Baseball-Reference).
By no means did Elston Howard have a bad career, but when he stacks up against a number of the other players that have won MVP awards, Howard is near that bottom of that list. That is not a bad thing since that list is filled with Hall of Famers.
Over 14 years in the majors, Howard posted a 108 OPS+ to go along with his .274 batting average.
Marty Marion was a player that was primarily known for his defensive abilities. His career dWAR was 25.0, a stark contrast to his career oWAR of 15.5 (h/t Baseball-Reference).
Marion won his National League MVP award in 1944 when he batted just .267 with six home runs and 63 RBI. During his career, Marion had a below average OPS+ of 81.
Zoilo Versalles picked up the American League MVP award in 1965 when he led the league in doubles, triples, runs scored and stolen bases. He was a big part of the Minnesota Twins' success that year.
While Versalles put up big numbers that season, he did not have a great career. He played 12 years in the majors and had a career batting average of .242. He also had a OPS+ of 82 and a 21.4 fWAR.
Picking up an MVP award as a relief pitcher is an incredibly difficult task. Jim Konstanty did just that during the 1950 season when he went 16-7 with a 2.66 ERA and a National League-leading 22 saves.
That season was by far the best of Konstanty's career as he went on to post fairly mediocre numbers during the rest of his time in the bigs. He retired with a 3.46 ERA and a 112 ERA+.
Just a few years into his career, it looked like Bobby Shantz was going to be a very good pitcher. Coming off an All-Star season in which he won 18 games, Shantz followed it up with 24 wins and the American League MVP in 1952.
Shantz moved into a relief role in 1956, but he was never as good as he was as a starter. He had a respectable 119 ERA+ to go along with his 119 wins during his career, well short of his short-lived MVP brilliance.
Phil Rizzuto was a key part of seven world champion New York Yankees teams, but he was never really a standout player. He picked up the American League MVP award during the best season of his career in 1950.
While Rizzuto is a Hall of Famer, there is certainly debate as to whether or not he deserves his spot in Cooperstown (h/t Murray Chass of The New York Times). Rizzuto had a 93 OPS+, but was known more for his fantastic defensive abilities. His spot on this list could certainly be argued, just as his spot in the Hall of Fame is.
For two seasons, Denny McLain was the best pitcher in the American League. He won back-to-back Cy Young awards in 1968 and 1969, and took home the AL MVP award when he won 31 games and posted a 1.96 ERA in 1968.
As good as McLain was in those two seasons, he didn't have an outstanding career, putting up an underwhelming 101 ERA+ during his 10 years in the major leagues.