The Mets promoted Lugo to the major leagues on June 30.[7] Lugo made his Major League debut against the Chicago Cubs on July 1, 2016, throwing two shutout innings in a victory.[8] On August 25, Lugo recorded his first major league win and hit, throwing five shutout innings against the St. Louis Cardinals at Busch Stadium before exiting with muscle cramps.[9] Following that, Lugo became a key cog in the Mets' injury-riddled rotation, pitching to a 2.67 ERA throughout the season and finishing with a 5–2 record. Lugo would have been the second or third starter for New York in the postseason had the Mets advanced past the Wild-Card Game.
Lugo chose to honor his paternal grandfather, who was Puerto Rican, by playing for the Puerto Rican national baseball team in the 2017 World Baseball Classic. He was the starting pitcher against Venezuela in the first round and against United States in both the second round and the Championship Game. He won both the first and second-round games.[10] In the Championship Game, Lugo did not have the same luck on the mound as Puerto Rico lost, 8–0.
Entering the 2017 season, Lugo was expected to provide depth the Mets' pitching staff. After injuries to other starters, Lugo found himself battling with Robert Gsellman for the final spot in the Opening Day starting rotation. However, Lugo himself would be diagnosed with a partial tear of the ulnar collateral ligament in his pitching arm after competing for Puerto Rico in the 2017 World Baseball Classic. The injury would cause him to miss the first two months of the regular season.[11] He returned to make his first start of the season for the Mets on June 11, 2017, against the Atlanta Braves, getting the win after pitching seven innings of one-run ball. On Saturday July 15, 2017, Lugo hit his first major league home run against the Colorado Rockies. On August 15, Lugo was again placed on the disabled list with an impingement in his pitching shoulder.[11] He returned on August 27, pitching 3+2⁄3 innings with 5 strikeouts in a pitch-limited start.[12] He continued making shorter starts throughout September, finishing the season with a 7-5 record and an ERA of 4.71, with 85 strikeouts and 25 walks over 101+1⁄3 innings pitched.[13]
Lugo performed very well the following season, posting a 2.66 ERA and 103 strikeouts in 54 games. He was once again effective in 2019, his first season in which he was exclusively a relief pitcher, posting a 2.70 ERA while striking out 104 batters and walking only 16 in 80 innings. Lugo struggled during the 2020 season, registering a 5.15 ERA and 3-4 record with 47 strikeouts in 36.2 innings of work.[14]
On May 17, 2021, Lugo was placed on the 60-day injured list after undergoing right elbow surgery.[15] He was activated on May 31.[16]
On December 22, 2022, Lugo signed a one-year contract with the San Diego Padres, containing a player option for the 2024 season.[18] Following the 2023 season, Lugo opted out of his deal, making him a free agent.
Kansas City Royals
On December 14, 2023, Lugo signed a three-year, $45 million contract with the Kansas City Royals.[19] In 2024, he was named to the All-Star team after having a stellar first half of the season in which he led the MLB in innings pitched (122), tied for the MLB lead in wins (11), and led all qualified American League pitchers in ERA (2.21).[20][21][22][23] On July 21, 2024, Lugo threw his first career complete game; in 9 innings, he struck out 6 batters and allowed 3 hits, no walks, and one earned run in a 4-1 win over the Chicago White Sox.[24] At the end of the season, he was 2nd place in the American LeagueCy Young Award balloting. [25]