Chris Shelton
You probably saw this coming. Few Detroit Tigers players encapsulate the fleeting nature of MLB success quite like Chris Shelton, who sandwiched a poor career around two stunning stretches of success. Most people remember his run to begin the 2006 season, when Shelton famously hit .471 with 9 home runs and 17 RBIs in the first 13 games of the season.
But that scorching start to 2006 was just a continuation of the arguably more impressive run he went on in 2005. From May 31, 2005 to May 31, 2006, Shelton hit .301 with 29 home runs and 87 RBIs in 160 games, good for 3.9 fWAR.
Then he turned into a pumpkin. By the end of July, Shelton was back in Toledo, and he played in only 50 more games in his big-league career, batting just .220 with 2 home runs.