Neftali Feliz, a right-handed pitcher from the Dominican Republic, began his Major League Baseball career with the Texas Rangers. Signed as an amateur free agent by the Atlanta Braves in 2005, he was traded to the Rangers in 2007 as part of a deal that sent Mark Teixeira to Atlanta. Feliz quickly rose through the minor league ranks, showcasing a powerful fastball that consistently reached the upper 90s, and made his MLB debut with the Rangers in August 2009.

In his rookie season, Feliz made an immediate impression as a reliever, appearing in 20 games and posting a remarkable 1.74 ERA with 39 strikeouts in 31 innings. His performance earned him a spot on the Rangers' postseason roster, where he continued to excel. The following year, Feliz was named the Rangers' closer, a role in which he thrived. In 2010, he saved 40 games, setting a rookie record for saves in a season, and was awarded the American League Rookie of the Year.

Feliz played a crucial role in the Rangers' bullpen during their back-to-back World Series appearances in 2010 and 2011. In the 2010 postseason, he recorded three saves and helped the Rangers reach their first-ever World Series, though they ultimately fell to the San Francisco Giants. The following year, Feliz was instrumental in the Rangers' return to the World Series, where they faced the St. Louis Cardinals. Despite his efforts, the Rangers were defeated in a dramatic seven-game series.

In 2012, Feliz transitioned from the bullpen to the starting rotation. However, his season was cut short due to an elbow injury that required Tommy John surgery, sidelining him for the remainder of the year and much of 2013. He returned to the Rangers in September 2013, but struggled to regain his previous form.

Over the next few years, Feliz's career was marked by a series of ups and downs. He was released by the Rangers in 2015 and subsequently signed with the Detroit Tigers. After a brief stint with the Tigers, he joined the Pittsburgh Pirates in 2016, where he showed flashes of his former self, posting a 3.52 ERA in 62 appearances. Feliz then signed with the Milwaukee Brewers in 2017, but was released mid-season after struggling with his performance.

Feliz continued to seek opportunities to revive his career, signing minor league deals with several teams, including the Kansas City Royals and Arizona Diamondbacks. In 2021, he made a brief return to the majors with the Philadelphia Phillies and later the Los Angeles Dodgers, though he was unable to secure a permanent spot on either roster.

Throughout his career, Feliz was known for his powerful fastball and ability to close out games under pressure.