Complex sentence: He has previously played for the Atlanta Thrashers, Anaheim Ducks, where he won his first Stanley Cup in 2007, and the Pittsburgh Penguins, where he won his second, third and fourth Stanley Cup in 2009,2016 and 2017.
Split into simpler sentences: He has previously played for the Atlanta Thrashers and Anaheim Ducks, the latter with whom he won a Stanley Cup in 2007. He won his second, third and fourth Stanley Cup with the Pittsburgh Penguins in 2009,2016 and 2017.