Conversation so far:
Why did Peter Forsberg return to the NHL in 2011?
Peter Forsberg returned in 2011 to play with the Colorado Avalanche.
Was Peter Forsberg well received by the Colorado Avalanche?
Peter Forsberg won two Stanley Cups with the Colorado Avalanche.
What was the Colorado Avalanche?
The Colorado Avalanche are a professional ice hockey team based in Denver, Colorado.
When did Peter Forsberg retire?
On 14 February 2011, hours before he was scheduled to play in front of the Avalanche's home fans at the Pepsi Center, Peter Forsberg announced his retirement from hockey.

Question: Why did he do this?
Self-contained rewrite: Why did Peter Forsberg retire?