Stadler started playing football in his local club Oberndorfer SK. His professional career started in 1979, when he came to
SV Austria Salzburg. In 1983, he signed for
Rapid Wien along with his close friend
Leo Lainer. But he did not play often for Rapid, so he left the club and played a short time for SK VOEST Linz. Then, he returned to Salzburg, who were in the second division. He had the most success as a player with Salzburg, becoming a double Austrian champion and reaching the final of the UEFA Cup in
1994 against
Inter Milan. His career ended in 1996 after 380 league matches (323 for Salzburg, 48 for Rapid, 9 for VOEST Linz) and 38 goals (36 for Salzburg, 2 for Rapid) ==Coaching career==