Before ...

Justin Morneau's career took off in his AL MVP season of 2006 at the age of 25. From Opening Day of 2006 to the day he suffered his concussion in Toronto he was putting up Hall-of-Fame-like numbers:

Totals: 693 games

.298 batting average

.372 on-base percentage

.528 slugging percentage

.900 OPS

136 home runs

171 doubles

526 RBI

Averages

per 162 games

32 home runs

40 doubles

123 RBI

97 runs scored

... and after

After the concussion Morneau never hit 20 home runs or drove in 100 runs in a season again (he did win the NL batting title in 2014). These were his numbers from 2011 to the end of his career in 2016:

Totals: 597 games

.275 batting average

.331 on-base percentage

.433 slugging percentage

.764 OPS

66 home runs

134 doubles

306 RBI

Averages

per 162 games

18 home runs

36 doubles

83 RBI

82 runs scored