Real world article
(written from a production point of view)
Josh Drennen is the actor who played Thalen in the Star Trek: Enterprise third season episodes "Proving Ground" and "Stratagem", but was replaced by Christopher Goodman for the character's appearance in "Azati Prime".
Drennen previously appeared in a 2001 episode of Roswell with Star Trek: Deep Space Nine guest star William Sadler and directed Allan Kroeker. Drennen was also seen in a 2006 episode of the UPN series All of Us with Richard Riehle. His other credits include a 1999 appearance on General Hospital and small roles in the films Red Zone (2001) and Self Medicated (2005).