When Adam LaRoche played for the Pirates, he was at best, mediocre, and seemingly incapable of hitting anything smaller than a beach ball prior to June. Over 3 years, he averaged 19 home runs a year, and batted .265. He hit 25 home runs one year, which is nothing to sneeze at, but was always a notoriously slow starter.
Now with Washington, LaRoche is batting .339 and is on pace to hit over 30 home runs. It seems this always happens to the Bucs, a player doesn't live up to expectations, he goes somewhere else, and does great.