Conversation so far:
What did Honus Wagner do late in Honus Wagner's career?
In 1910, Wagner's average fell to .320, his lowest average since 1898.
what sports did he play?
baseball.
Did he play any other sports?
CANNOTANSWER.
Did he do any coaching in his late career?
CANNOTANSWER.
What else can you tell me about this time period?
Wagner has been considered one of the very best all-around players to ever play baseball since the day he retired in 1917.

Question: Why did he retire?
Self-contained rewrite: Why did Honus Wagner retire?