Nimmo played ten games with the Gulf Coast Mets and the Kingsport Mets towards the end of the season. He combined to hit.211 with four runs batted in. He spent the following season with the Class A-Short SeasonBrooklyn Cyclones of the New York–Penn League. On July 30, Nimmo posted the first four-hit game of his career, falling just a triple short of the cycle, with three runs scored and two RBIs to lead the Cyclones in a 10–5 win over the Mahoning Valley Scrappers. On August 18, Nimmo capped a career-high six-RBI night with his second grand slam of the season. Nimmo is the only player in the New York–Penn League with two grand slams in, his first coming on June 30. For the season, Nimmo batted.248 with six home runs and forty RBIs in 266 at bats. Nimmo placed fourth in doubles and fifth in RBIs for the New York–Penn League. Nimmo began the season with the Class-ASavannah Sand Gnats and was ranked fourth among Mets prospects. By April 17, Nimmo was the leading hitter in the South Atlantic League with a.447 batting average, earning him a SAL mid-season All-Star nod. He was also voted into the All-Star Futures Game held at the Mets' Citi Field. By season's end, his batting average fell to.273 with two home runs and forty RBIs. His performance at the plate was considered underwhelming as he averaged more than a strikeout per game. His numbers may have been hampered by a spacious home ballpark in Savannah that's tough on lefty power hitters, as well as a wrist injury that caused him to miss some games. Nimmo started the season with Class-A Advanced St. Lucie Mets of the Florida State League. After batting.322 with four home runs, 25 RBIs, a.448 on-base percentage and.458 slugging percentage to earn FSL All-Star honors, he received a mid-season promotion to Double-A Binghamton Mets on June 19. Between his two clubs, Nimmo posted a.278 Avg, 10 HR and 51 RBI. After a brief four game stint with St. Lucie at the start of the season, Nimmo was promoted to the Binghamton Mets. He suffered a knee injury on April 29 that caused him to miss some playing time. Prior to the knee injury, Nimmo was batting.297 with a.368 on-base percentage and a.420 slugging percentage in 34 games. On July 28, it was announced that Nimmo was promoted to the Mets Triple-A affiliate, Las Vegas 51s as the starting center fielder. Once again, his season was interrupted by injury when he fouled a baseball off his nose in a batting cage. The Mets added him to their 40-man roster after the season to protect him from the Rule 5 draft.
Major league career
2016
Nimmo began the season with the Las Vegas 51s; through 250 at bats he was hitting.328 with five home runs and 37 RBIs. Nimmo was promoted to the Major Leagues on June 25 to replace the slumping Michael Conforto whose batting average had fallen to.130 since May 1. He made his major league debut the next day against the Atlanta Braves and went 0-for-4. On June 27, his second game, Nimmo recorded his first hit and his first run against Washington Nationals pitcher Joe Ross and went 2-4 overall. On July 1, he hit his first home run, a three-run homer against Jason Hammel of the Chicago Cubs, making the game 7–1 in the bottom of the fourth inning. On July 17, Nimmo was sent down to the Triple-A Las Vegas 51s after batting.235 with one home run and four RBIs in 51 at-bats. On July 29, Nimmo was once again promoted after Juan Lagares suffered a torn thumb ligament and undertook surgery to repair the injury.
2017-18
In 2017, Brandon Nimmo was chosen to be part of Team Italy in the World Baseball Classic. While playing in the World Baseball Classic, Nimmo strained his right hamstring. The injury left him unable to join the Mets Opening Day roster, and when he recovered in late April, he began his season in the minor leagues. He remained with Las Vegas until June 16, when injuries to Juan Lagares and Matt Harvey led to Nimmo and Matt Reynolds returning to the Major Leagues. Nimmo started strong, hitting.350/.458/.400 over 24 plate appearances. However, he was placed on the disabled list with a partially collapsed lung on July 8 and would not return until July 28. Nimmo would finish the 2017 season appearing in 69 games for the Mets, batting.260/.379/.418 with 5 home runs. Late in the year, hitting coaches Kevin Long and Pat Roessler suggested that Nimmo try hitting without his front foot striding forward. Nimmo took the suggestion, which allowed his front foot to turn open and generate better hip rotation. Up until that August, Nimmo had slugged.346 in his career. He slugged.479 in September and continued to show increased power in 2018, slugging over.500 through the season's first two months. In 2018, Nimmo batted.263/.404/.483, with 17 home runs and 47 RBI. He led the majors in hit by pitch, with 20.
2019
On April 17, 2019, Nimmo was taken out of the first inning of a game due to a stiff neck, and missed two games. On May 21, he once again experienced neck stiffness and went on the injured list. He was later found to have a bulging disk in his neck and went through a rough rehabilitation assignment, not appearing in the Mets' lineup again until September 1. In 2019, Nimmo batted.221/.375/.407 with 8 home runs and 29 RBIs in 69 games.
