Thelen has worked as multiple clubs around Texas, usually in the southeast part of the state and in the Houston area. Among his stops were stints as the director of instruction at The Traditions Club at Texas A&M in Bryan; pro at The Falls Resort and Golf Club in New Ulm; and at Bushwood Golf Center in Houston.
On the European Senior Tour this year, Thelen has made 14 starts and posted three victory, plus one more Top 10. His three wins came at the Berenberg Bank Masters in Germany, the Bad Ragaz PGA Seniors Open in Switzerland, and the Fubon Senior Open in Taiwan.
The third win lifted Thelen up to third place on the tour's money list, and guaranteed him a Top 4 finish on the money list. That's important because it gets him a spot in the field at the 2013 U.S. Senior Open.