During the 2020 pandemic-induced shutdown, Alonso honored those who went "above and beyond their call of duty" through his newly-launched Homers for Heroes foundation...The foundation honored a hero after each of the Mets' 60 games that season... Each hero received a care package, which included game-used memorabilia from Alonso...Was given the nickname "Polar Bear" by Todd Frazier during Spring Training in 2019...Used a custom-designed bat during All-Star week and Players' Weekend, named "Haley's Comet" in honor of his fiancée... Using that bat, won the Home Run Derby...Hit his 41st home run of the 2019 season with the bat, tying the Mets' single-season record...Designed custom-made, 9/11-themed cleats for himself and his teammates for the Mets' home game on Sept. 11, 2019, vs. Arizona...Donated the cleats to the National September 11 Memorial & Museum on Oct. 1, 2019...Donated 10 percent of his $1 million Home Run Derby winnings to charity, giving $50,000 to Wounded Warrior Project and $50,000 to the Stephen Siller Tunnel to Towers Foundation.
Tied for seventh in the majors and tied for third in the NL with 16 home runs...Finished the year on a power streak, blasting 10 homers in his final 22 games...Tied for eighth in the NL with six hit-by-pitches...Tied for second in MLB with 10 homers in September...Had three multi-homer games, tied for the most in the NL: Aug. 17 at Miami, Sept. 6 vs. Philadelphia and Sept. 27 at Washington...Nearly one-third of his hits came against Washington (15 of 48)...Hit .429 (15-35) with three doubles and four homers vs. the defending World Champions...Belted his first career walk-off home run on Sept. 3 vs. the Yankees...His walk-off blast vs. the Yankees was the Mets' second-ever walk-off home run in the Subway Series and the third by either team in a regular-season Subway Series game.
Became the sixth Met to be named the BBWAA NL Rookie of the Year...Named the Players' Choice NL Rookie of the Year...Also was Baseball America's MLB Rookie of the Year, the Baseball Digest NL Rookie of the Year and Sporting News NL Rookie of the Year...Was named a Topps Rookie All-Star.... Finished in seventh place in the National League MVP voting.... In his first major league season, set Mets single-season records for home runs (53), extra-base hits (85) and total bases (348) while also establishing club rookie records for hits (155), RBI (120), runs scored (103), at-bats (597), plate appearances (693), games played (161), slugging percentage (.583), OBP (.358) and OPS (.941)...Also tied the club rookie record with 72 walks...Was the eighth Met ever to record a 100-RBI, 100-run season.... Led the majors with 53 homers and was fourth with 120 RBI...Finished tied for third with 85 extra-base hits, 10th with a .583 slugging percentage and 11th with a .941 OPS...Was third in the majors with 183 strikeouts...Tied for fifth in the majors with 21 hit by pitches.... Led all qualified rookies in games played, hits, home runs, RBI, OPS, extra-base hits, runs scored, walks, total bases and slugging percentage...Ranked second in multi-hit games (42) and third in doubles (30). Was the NL Rookie of the Month for April, June and September 2019, making him the Mets' first three-time winner of the award...Jacob deGrom, who earned the honor twice in 2014, is the only other Met to win the award multiple times in a season since it began in 2001...The only other three-time winners of the award in the NL are Jason Bay (2004) and Juan Soto (2018).... Finished with the second-most RBI (120) and extra-base hits (85) ever by an NL rookie in the modern era...Only Albert Pujols has had more (130 RBI, 88 extra-base hits in 2001).... Was named to the Opening Day roster and made his major league debut as the starting first baseman in the Mets' season opener at Washington...Became the seventh player (only first baseman) in Mets history to make his major league debut in a start on Opening Day...Notched his first career hit, a single, in the eighth inning.... Reached base safely in 34-straight games from August 2-September 9, the longest streak ever by a Mets rookie and the longest single-season streak in team history...Batted .314 (43-137) with seven doubles, 13 homers, 32 RBI and 23 runs scored during the streak with a 1.043 OPS...Was tied for the longest streak in the NL (also, Max Muncy).... Homered in four-straight games from August 5-9...The only other Mets rookie with a four-game homer streak is Larry Elliot (July 21-24, 1964).... Went deep in three-straight games twice, April 6-9 and September 17-20...Homered in consecutive games May 20-21, June 22-23, July 17-18, September 3-4 and September 27-28.... His 33 multi-RBI games were the fourth-most in the majors...Mike Piazza (35 in 1999 and 2000) is the only player in franchise history with more.... Finished tied for seventh in the majors with 13 games with at least three RBI...Carlos Beltrán (14 in 2008) is the only Met with more in a season.... Set the club rookie record for home runs in a month with a major league-leading 11 September round-trippers...Also had 10 homers in May.... Had two walk-off RBI, a sacrifice fly in the 10th inning of a 5-4 win on April 30 vs. Cincinnati and a bases-loaded walk on September 6 vs. Philadelphia in the bottom of the ninth inning.... Hit a home run in 16 different ballparks, a rookie record and the most by a Met since Mike Piazza (18 in 2000)...Had four multi-homer games, tied for the most by a Mets rookie (also, Darryl Strawberry in 1983).... Led the majors with 18 homers and 48 RBI in the seventh inning or later...His 48 late-inning RBI were a Mets record...Todd Hundley (21 in 1996) is the only Met with more late-inning home runs in a single season. ... In the first half, set NL rookie records with 30 home runs and 68 RBI...Only Mark McGwire (33) in 1987 had more pre-break homers as a rookie... Set a major league rookie record with 53 extrabase hits before the All-Star break. ... Was the fourth player in NL history (11th overall) with at least 30 homers and 20 doubles before the All-Star break...Tied a franchise record with
30 homers before the All-Star break (also, Dave Kingman, 1976).... Clobbered his first big-league homer in the ninth inning on April 1 at Miami, a 444-foot, three-run blast off Drew Steckenrider in a 7-3 win.... Blasted a 458-foot homer off the face of the third deck at Citi Field on June 15...Was the longest homer by a Met at Citi Field in the Statcast ERA (2015-present).... Was named NL Player of the Week for June 17-23...Went 10-24 (.427) with four homers and a 1.590 OPS during the week...His home run on June 23 was his 27th of the season, setting a Mets rookie record. Drilled a Statcast-estimated 474-foot, two-run homer into the third deck at Target Field on July 17...Was the longest blast by a Met since tracking began in 2015.... Belted a go-ahead homer in the 16th inning on July 18 at San Francisco...Was the second Mets rookie to homer in the 16th inning or later (also, Tim Harkness' walk-off homer, September 1, 1963).... Hit his first career pinch-hit homer, a three-run shot, on July 20 at San Francisco.... Set career-high marks with five hits and six RBI on August 15 at Atlanta and reached base in all six of his plate appearances, going 5-5 with a homer and a walk...Hit his 39th homer in that game to tie the NL rookie home run record...He became just the fourth Mets rookie with at least six RBI in a game and the sixth rookie in team history to
produce a five-hit game.... His 40th homer on August 18 at Kansas City established a new NL rookie record, passing Cody Bellinger (39, 2017).... Set the Mets' single-season home run mark with his 42nd homer on August 27 vs. the Cubs...Passed Todd Hundley and Carlos Beltrán (41).... Set the all-time rookie home run record with his 53rd blast on September 28 vs. Atlanta off Mike Foltynewicz...Passed Aaron Judge (52, 2017).
Began and spent most of the season with St. Lucie (A) of the Florida State League...Promoted to Binghamton (AA) of the Eastern League on August 24...Named a MiLB organization All-Star and a Baseball America High Class-A All-Star...Selected to the Florida State League postseason All-Star team...Was tied for second in the FSL in homers (16) and was tied for 10th in RBI (58)...Was the FSL Player of the Week twice (June 19-25 and July 17-23)...Earned Florida State League Player of the Month honors in July after hitting .336 (39-116) with seven doubles, eight homers and 26 RBI...Hit safely in nine of his 11 games (14-45, .311) with the Rumble Ponies, including a two home run performance against Erie on August 30...Placed on the Disabled List on April 12 with a broken left hand after being hit by a pitch while playing against Bradenton Marauders on April 11...Returned to action on May 26.
Made his professional debut for Brooklyn (A) of the New York-Penn League on July 9 against Hudson Valley, going 1-4 with a double...Named a mid-season New York-Penn League All-Star...Was a Baseball America short-season All-Star.