Originally recruited from Charlton, Teasdale was a sensational Under 19s forward with Richmond and made a huge impact in his debut season. However, he lost form and was traded to the Swans as part of the deal which took John Pitura to Richmond. Teasdale had initial success with the Swans as a full-forward, but struggled again before coach Ian Stewart threw him into the ruck in a match against St Kilda in 1977. Teasdale played brilliantly for the rest of the season and won the Brownlow Medal that year. A superb high mark and a long kick, Teasdale was idolised by South fans. However, he stood out of football in an effort to leave the club and finally won a release to Collingwood where his career was dogged by knee injuries that restricted him to 14 games across two seasons.