Former Chicago Cubs slugger Sammy Sosa said his jersey No. 21 should be retired and its continued use shows the strain in his relationship with his old team.

Cubs rookie outfielder Tyler Colvin wears No. 21. Former Cubs pitcher Jason Marquis also wore it from 2007-08.

A Cubs spokesman did not return a call to comment.

Sosa hit 545 home runs as a Cub from 1993-2005 and is one of seven players with more than 600 career home runs. He is the only player in history to have three seasons of 60-plus home runs.

Sosa was dogged by steroid rumors until the New York Times reported last summer that he was on a list of 104 players who tested positive for steroids in 2003. Asked about the 2003 test by Chicago Magazine, Sosa said: "I don't want to talk about that. Let's talk about something else."

The Cubs traded Sosa to the Baltimore Orioles after he left the final game of the 2004 season early, angering some teammates and management. He spent one unproductive season in Baltimore and then sat out the 2006 season. Sosa retired after batting .252 with 21 home runs and 92 RBIs with the Texas Rangers in 2007.

Chicago has retired jersey numbers of six former Cubs: Ernie Banks (14), Ron Santo (10), Ryne Sandberg (23), Billy Williams (26), Greg Maddux (31), Fergie Jenkins (31). Jackie Robinson's No. 42 was retired by Major League Baseball in 1997.