On April 17, 2015, Vázquez made his major league debut by coming in to pitch the top of the ninth inning in a 7–2 win over the Philadelphia Phillies. He pitched one inning, allowing two hits and one run while striking out two batters. He went on the disabled list due to gastrointestinal bleeding on April 22. On June 1, the Nationals called up Vázquez to the major leagues from Syracuse. At the end of the season, Vázquez was able to reach with his fastball in relief. In 49 games for the Nationals, he pitched in innings, posting a 2–1 record with a 2.79 ERA. With Jonathan Papelbon suspended and Drew Storen injured, Vázquez converted two save opportunities during the final week of the season. He finished the season with a 2.79 earned run average. During the 2016 season, Vázquez's ERA reached a peak at 6.82 following a game on June 18 where he allowed all six batters he pitched to, to reach base. In the next 13 appearances, he had a 0.93 ERA to lower his season ERA to 4.53.
Pittsburgh Pirates (2016–present)
2016–17
On July 30, 2016, the Nationals traded Vázquez, along with Taylor Hearn, to the Pittsburgh Pirates for Mark Melancon. For the Pirates, he finished with a 3.29 ERA in 28 games. Vázquez began the 2017 season as a setup reliever. After a 0.58 ERA in 31 games, on June 9 he was named co-closer for the Pirates along with Juan Nicasio, replacing Tony Watson. Vázquez later assumed primary closing duties, with Nicasio becoming the eighth-inning setup man. Vázquez was 5–3 with a 1.67 ERA, and earned 21 saves in 23 opportunities in 2017. His fastest pitch of 2017 was 102.6 miles an hour, second-best in MLB only to pitches by Aroldis Chapman. Of all MLB pitchers, he held left-handed batters to the lowest batting average,.082.
2018–19: All-Star seasons
Before the 2018 season, Vázquez signed a four-year contract with the Pirates, with club options for another two years. In 2018, Vázquez was selected to play in the 2018 All-Star Game, his first All-Star appearance. For the season, he was 4–2 with 37 saves and a 2.70 ERA. In an April 7, 2019, game against the Cincinnati Reds, Vázquez was ejected after his role in a bench-clearing incident involving Chris Archer, Derek Dietrich, Yasiel Puig, Amir Garrett, Keone Kela, and David Bell. Vázquez was selected for the 2019 All-Star Game, as a roster replacement for Zack Greinke. On September 10, Vázquez and Kyle Crick got into a clubhouse fight; Crick broke his finger, requiring season-ending surgery. On September 17, the Pirates placed Vázquez on the restricted list, due to his [|arrest on multiple charges] of unlawful contact with a minor. At the time, his record for the season was 5–1 with a 1.65 ERA and 28 saves. He was also placed on administrative leave by Major League Baseball.
Pitching style
Vázquez throws a fastball which can reach over. Vázquez's fastball averaged in 2016 and around in 2017. As a prospect with the Rays, Vázquez initially threw only. He also throws an effective changeup at with two-seam movement, which he picked up in the Rays minor league system. Vázquez began throwing it frequently in 2015, and uses it around 25 percent of the time. The pitch has been referred to as a "Bugs Bunny changeup" by Pirates pitching coachRay Searage. Vázquez also throws a slider and a curveball.
Personal life
In 2018, he changed his last name from Rivero to Vázquez to match the surname of his sister, citing that she had been a big part of his career.
Sexual assault
Vázquez was arrested on September 17, 2019, on charges of computer pornography, specifically alleging that he solicited a child and provided obscene material to minors, regarding an alleged sexual relationship he had with a 13-year-old female from Lee County, Florida. Hours later, Vázquez was charged with statutory sexual assault, unlawful contact with a minor, corruption of minors and indecent assault of a person less than 16 years old related to a separate incident in Westmoreland County, Pennsylvania. Vázquez admitted that in 2017, when the girl was 13 years old, he had a sexual encounter with her that he described as "sex, but not really" because he could not fully insert his penis into her vagina after a minute of trying. He also admitted to sending nude photos of himself and videos of himself engaged in sexual activities to the girl. An additional 21 felony charges were announced on November 19, 2019, and Vazquez was denied bail.
