Simplify the following text for a Grade 9 native English-speaking person.
Original: Griffey Junior played for the Seattle Mariners , Cincinnati Reds , and the Chicago White Sox before his retirement in 2010 .
Simplified: Griffey , playing for the Seattle Mariners in two separate tenures with them , Cincinnati Reds and the Chicago White Sox , won 10 Gold Glove awards and appeared in 13 All-Star games . Upon his retirement , AP noted : `` In his prime , Ken Griffey Jr. was considered the best player in baseball . ''