2) Andy Messersmith
Andy Messersmith spent most of his career in Southern California playing baseball for the Angels and Dodgers. His career began with the Angels in the 1968 season before he'd eventually go on to play two separate stints with the Dodgers.
Messersmith began his MLB career primarily as a reliever, but by his second season he was already one of the better starting pitchers in the American League after he posted a 2.52 ERA in 40 appearances (33 starts) and 250 innings of work. He even received some MVP consideration that year, finishing 29th on the AL Ballot.
His five years with the California Angels were outstanding, as he posted a 2.78 ERA in 168 appearances (123 starts). He didn't win a Cy Young award and only made the all-star team once, but this right-hander was certainly an ace for his half-decade in Anaheim.
After the 1972 season, the Angels opted to trade him to the Dodgers in a deal involving another legend to play for both teams, Frank Robinson. The Angels got a couple of solid years out of the future Hall of Famer, but the Dodgers got three outstanding years out of Messersmith. The former Angels hurler made the all-star team in 1974 and 1975 for the Dodgers, finishing in the top five of the NL Cy Young balloting both years. He finished as the NL Cy Young runner-up in 1974 and led the league with 321.2 innings in 1975. The final year of his career was spent in Dodger Blue as he made 11 starts for them in 1979 after stops in Atlanta and New York with the Yankees.
Messersmith is a prime example of a player who excelled with both of these franchises. He wasn't with either one for incredibly long, but he sure was impactful.