The center made a move to Jokerit after playing the beginning of the 2014-15 season for Fribourg in the Swiss League. Wirtanen has been a staple for the Finnish national team for several years.
Wirtanen played in the KHL for Donbass Donetsk for two seasons from 2012 to 2014, scoring 11+20=31 in 102 regular season games. During his second season at Donbass, the team made it to the second round of the KHL playoffs. At Donbass, Wirtanen played on the same line with Finnish forwards Tuomo Kiiskinen and Teemu Laine.
The Hyvinkää-born player is known for his strong two-way game and shorthanded play. One of his strengths are faceoffs. During 2013-14, Wirtanen was one of the faceoff leaders in the KHL with a 60.8 winning percentage.
In the Finnish Elite League, the center has played for HPK and HIFK, winning the Finnish Elite League championship for both. At HPK, he also netted a third place in the Finnish Elite League. Wirtanen played three seasons in North America, including a stint with the Anaheim Mighty Ducks in the NHL.
Wirtanen played his Finnish national team debut game during the 2010-11 season. He was a member of the team that won silver at the Minsk IIHF Ice Hockey World Championships in 2014.