Trnka was drafted 106th overall by the Mighty Ducks of Anaheim in the 1994 NHL Entry Draft and started his NHL career with the Ducks in 1997 and stayed there for six seasons before he was traded to the Florida Panthers for Sandis Ozolinsh and Lance Ward. In total, Trnka played 411 regular season games, scoring 14 goals and 63 assists for 77 points and collecting 323 penalty minutes.
Trnka was drafted 106th overall by the Mighty Ducks of Anaheim in the 1994 NHL Entry Draft. He started his NHL career with the Ducks in 1997, where he played for six seasons before being traded to the Florida Panthers along with Sandis Ozolinsh and Lance Ward. Over his career, Trnka participated in 411 regular season games, scoring 14 goals and 63 assists for a total of 77 points while accumulating 323 penalty minutes.