Sirtautas started his professional career in
Atletas Kaunas, in 1989. After a few seasons with the team, he became a team leader, and while playing alongside
Saulius Štombergas and
Žydrūnas Ilgauskas, managed to lead the team to the
LKL Finals twice. During his last season with the team, he averaged 15 points per game. After that successful season,
Lithuania national team coaches invited Sirtautas to the training camp for the upcoming
EuroBasket, but he did not make it onto the final roster. In 1995, he moved to his former rival team,
Žalgiris Kaunas. He was one of the main contributors to the team, averaging more than 10 points per game, over the next three seasons, despite having to share his minutes with stars like
Rimas Kurtinaitis,
Darius Lukminas, and
Ennis Whatley. While playing for Žalgiris, he participated in the
LKL Slam Dunk Contest, and he won the
slam dunk title three times in a row. In 1998, Sirtautas moved to
Slovakia, where he played with Slovakofarma Pezinok, in the
FIBA Saporta Cup. He recorded 7.8 points and 1.2 steals per game in that tournament. Returning to Lithuania the following season, Sirtautas signed with Suvalkija Marijampolė. However, the team went bankrupt at the end of the season, and he was forced to look for a club elsewhere. In 2000, he moved to China, and signed with
Junan Jinan, of the
Chinese Basketball Association (CBA). During the 2001–02 season, he played alongside fellow Lithuanians
Rolandas Urkis and
Martynas Purlys. In March 2002, Sirtautas moved back to Lithuania, and he finished the season with
Alita Alytus. Sirtautas played for the Estonian club Audentes Tallinn, during the 2002–03 season. In April, he once again moved back to Lithuania, and after playing two more seasons, he retired in 2005. ==Coaching career==