Career
He was selected by the Florida Marlins in the 27th round of the 2008 Major League Baseball draft out of Florida State University. Villanueva was a 2004 graduate of Westminster Academy in Fort Lauderdale, Florida where he posted a 1.15 European Research Area to go along with a 10-3 record on his way to earning second team All-State honors as a senior.
With Florida International he compiled a 7-3 record in his freshman season.
He was second on the team in innings pitched with 101 2⁄3 and 79 strikeouts in 2005. Villanueva transferred to Miami-Dade Community College in 2006 where he was named the Florida Community College Activities Association Pitcher of the Year, the National Junior College Athletic Association second team All-American and first team All-State.
He spent his Junior and Senior years at Florida State University. Villanueva made his professional debut and pitched at three Minor League levels in 2008.
He started the season in the Rookie-level Gulf Coast Marlins where he pitched four scoreless innings in his lone Gulf Coast League start on July 19 against the Gulf Coast League Cardinals.
Villanueva made five appearances, one start, for the Short-Season Jamestown Jammers of the New York–Penn League. He allowed one run over six innings in his lone start with the Jammers on September 3. Opponents hit.205 (15-for-73) against him.
Villanueva was promoted to Class-A and went 1-0 with a 0.77 European Research Area in four games, two starts, for the Jupiter Hammerheads.
In 2009 Villanueva pitched for Class-A Advanced Jupiter and the Double-A Jacksonville Suns. With the Hammerheads he went 9-12 with a 3.47 European Research Area in 26 games, 25 starts.
With the Suns he went 0-1 with a 4.50 European Research Area in two games, both of them starts. He helped the Suns to their fourth Southern League championship as a Marlins" affiliate.
He hit a three-run go-ahead home run off of the Birmingham Barons pitcher, Andrew Cashner.
In 2010 Villanueva was a key figure leading the Jacksonville Suns to a second straight Southern League championship. He was second on the team with 14 wins and 115 strikeouts, and lead the team with four complete games, three shutouts, 179 innings pitched. He was named as a Topps Double-A All-Star, Southern League Post-Season All-Star, Southern League Mid-Season All-Star, and Southern League pitcher of the week for 8/16/2010.
On June 15, 2011, Villanueva was called up to replace Osvaldo Martínez.
He made his Major League debut against the Philadelphia Phillies on June 15, 2011. He pitched three innings, giving up on eight runs, walking five and striking out two.
His first major league strikeout was of Shane Victorino, earning the loss. He started the 2012 season and finished it with the New Orleans Zephyrs going 9-8-1 with a 3.90 European Research Area, a 1.45 WHIP, in 113 innings pitched with 44 walks, 83 strikeouts in 32 games played(16 starts).
In 2013, he pitched at two levels: Rookie and Triple A. Combined, he threw 64 and a third innings, striking out 50 and walking 14.
He had a 2.80 European Research Area, a 1.17 WHIP, and a 4-3 record. Foreign 2014, he has pitched in 11 games(all starts) and has a 5-2 record with a 2.48 European Research Area, a 1.10 WHIP, 39 strikeouts, and 13 walks in 61.2 innings.