After going undrafted, Gaudreau signed with Milwaukee of the American Hockey League on June 12, 2014, and had 11 points (four goals, seven assists) in 43 games. Gaudreau also was loaned to Cincinnati of the ECHL and played 14 games. Milwaukee signed him to a one-year contract for the 2015-16 season. His offensive numbers opened eyes, and the Nashville Predators signed him to a two-year, entry-level contract on Jan. 5, 2016.

Gaudreau spent parts of three seasons with Shawinigan of the Quebec Major Junior Hockey League from 2011-14, which included winning the Memorial Cup championship in 2012, his first season. In 2013-14, he was traded to Drummondville and had 40 of his 71 points that season in 36 games after the trade. Gaudreau took one minor penalty all season and was named the QMJHL's most sportsmanlike player.

Gaudreau spent parts of three seasons with Shawinigan of the Quebec Major Junior Hockey League from 2011-14, which included winning the Memorial Cup championship in 2012, his first season. In 2013-14, he was traded to Drummondville and had 40 of his 71 points that season in 36 games after the trade. Gaudreau took one minor penalty all season and was named the QMJHL's most sportsmanlike player.

After going undrafted, Gaudreau signed with Milwaukee of the American Hockey League on June 12, 2014, and had 11 points (four goals, seven assists) in 43 games. Gaudreau also was loaned to Cincinnati of the ECHL and played 14 games. Milwaukee signed him to a one-year contract for the 2015-16 season. His offensive numbers opened eyes, and the Nashville Predators signed him to a two-year, entry-level contract on Jan. 5, 2016.

In 2016-17, Gaudreau attended training camp with Nashville but was reassigned to Milwaukee. He was recalled Oct. 22, 2016, and made his NHL debut that night before being returned to Milwaukee. He got his first NHL point, an assist, in a 5-3 win at the Colorado Avalanche on Nov. 29, 2016. It was his only point in nine games with Nashville.

But injuries gave Gaudreau a chance to play in the 2017 Stanley Cup Playoffs, and he made the most of the opportunity. Gaudreau scored three goals in six games in the Stanley Cup Final against the Pittsburgh Penguins, including the winning goals in Games 3 and 4. He became the first player since Johnny Harms of the Chicago Black Hawks in 1944 to score his first three career NHL goals in a Stanley Cup Final.

Despite his playoff heroics, Gaudreau spent most of the 2017-18 season with Milwaukee, finishing with 43 points (22 goals, 21 assists) in 54 games. He did get into 20 games with the Predators and had three assists.

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