Mueller came to the Cubs from the Giants in a trade for pitcher Tim Worrell. He joined the long list of mediocre players to man third base since Ron Santo was traded after the 1973 season.
It wasn't a good year for Mueller. It started well, as he was hitting .317 with 5 homers in the first 36 games. But on May 13 he got hurt.....hurt badly. He suffered an open fracture of his left knee cap after sliding into metal beneath the padding along the left field wall at Busch Stadium. He had surgery that same day.
The injury cost him three months. He struggled when he returned, but got hot towards the end of the season to bring his numbers back up. He ended the year with an average of .295 plus 6 HRs and 23 RBIs over 70 games.
The next season his number dropped a bit, and with free agency on the horizon after the season, the Cubs dumped him back to the Giants in September. In return the Cubs got a pitching prospect named Jeff Verplancke. The guy never threw an inning for any Cub team on any level. He had Tommy John surgery in 2003 and was later traded back to the Giants.