Aguilera was summoned by the Mets from AAA when Bruce Berenyi went down with an injury in 1985; as the Mets’ fifth starter, he went 10-7 each of his first two years at Shea. He pitched three innings of scoreless relief in the Mets’ dramatic 16-inning LCS clincher over the Astros in 1986, but was hit hard in Game Two of the World Series in relief of loser Dwight Gooden. Aguilera also surrendered two tenth-inning runs in Game Six, but was the winning pitcher after the Mets’ spectacular three-run comeback in the bottom of the inning.
His best season as a starter, an 11-3 mark in 1987, was interrupted by three months on the DL in the middle of the year. An elbow operation kept Aguilera out for most of 1988, and David Cone took his place in the rotation. Aguilera was used in relief in 1989 and, throwing harder than previously, he soon won the righthanded closer role from Roger McDowell. Dealt to the Twins in mid-season with David West, Tim Drummond and Kevin Tapani in the five-man package that brought Frank Viola to the Mets, Aguilera returned to a starting role until the end of the season.
But it was in the bullpen that Aguilera would prove his worth to the Twins. Asked to replace Jeff Reardon as closer when the veteran fireman left for Boston as a free-agent after the 1989 season, Aguilera saved 32 games for the last-place Twins. His 2.76 ERA was the lowest of any Minnesota pitcher with more than five appearances; in 75 innings of work, he walked just 17 batters. Even as a starter, the right-hander had displayed exceptional control; his deadliest pitch was a nasty slider, especially effective against left-handed batters. In the bullpen, Aguilera came to rely mainly on a good, sinking fastball and an above-average splitter. Over the next five seasons, Aguilera averaged 35 saves and just under 18 walks a year.
In 1991, Aguilera tied Reardon’s single-season club record with 42 saves, adding five in the postseason as the Twins won their second World Series title in four years. In July, he made the first of three consecutive All-Star appearances. The following season, Aguilera passed Ron Davis to become the Twins’ all-time save leader, finishing the season with 41.
Over the next few years, the aging Twins slipped into the AL cellar and team management tried to move him to a contender. Aguilera’s multi-million-dollar salary was hard to justify for a second-division club, despite another solid season (23 saves, with just seven unintentional walks) in 1994. On July 6, just hours before he would have become a ten-and-five player (having spent ten years in the majors and five with the same team, Aguilera would be have been able to veto any transaction) Minnesota sent him to Boston in exchange for rookie pitcher Frankie Rodriguez.
Replacing an inconsistent committee of closers, Aguilera earned his first save with the Red Sox the following night against his former club at the Metrodome. He finished the season with twenty saves in twenty-one opportunities (giving him 32 saves overall) but gave up a game-tying homer to the Indians’ Albert Belle in the eleventh inning of Game One of the AL Division Series. It was Aguilera’s only appearance as Cleveland swept Boston in three games.
A free agent after the season, Aguilera fielded lucrative offers from various contenders but chose to return to Minnesota with a three-year, $9 million contract. Faced with a dearth of reliable starters, manager Tom Kelly moved Aguilera back to the rotation in spring training. Aguilera missed the first two weeks of the season thanks to an arm injury aggravated while lifting a suitcase; even after recovering, he found it hard to re-adjust to a starting role. He finished the year with a respectable 8-6 record but posted an unimpressive 5.42 ERA. On September 7 (Kirby Puckett Night at the Metrodome) Aguilera suffered a season-ending hamstring pull.
Concerns about his durability forced Aguilera back to the bullpen at the start of the 1997 season. He ended up serving as the team’s closer for the entire season, saving 26 games. In 1998, he tacked on 38 saves despite a 4.24 ERA and mid-season rumors that he would be traded to a contender for the stretch drive. In fact, it wasn’t until the following May that he was dealt — to the Chicago Cubs, for two minor-leaguers. Aguilera spent his final two seasons with the Cubs, calling it quits after a 29-save season in 2000.
Aguilera hit .278 in his first major league season and was used as a pinch-hitter, most notably in Game Three of the 1991 Fall Classic, when he became the first pitcher since Don Drysdale (in 1965) to pinch-hit in a World Series game. Facing the Braves’ Jim Clancy, Aguilera flied out with the bases loaded to end the 12th and eventually lost the game in the bottom of the inning on an RBI single by Mark Lemke. He was a third baseman at Brigham Young University, where he played on the same team with Cory Snyder, Wally Joyner, and Scott Nielsen.