Newell's won the 1987-88 Primera División.
In 1990 Theiler joined River Plate bet he never established himself in the first team, he then had a spell with St Gallen of Switzerland before returning to Argentina to join San Lorenzo de Almagro.
In 1993, he returned to Newell's Old Boys.
After retiring as a player he went on to pursue a career in coaching.
After working with the youth teams of River Plate and Newell's Old Boys he became the manager of Libertad of Paraguay in 2004 for three games.
In 2005, he had a brief spell as the manager of Instituto de Córdoba.
In 2008, he was the manager of the Argentina Under-15 football team for the South American Under-15 Football Championship.