There has never been a better rookie season in the history of the Mets than Pete Alonso, the Polar Bear, had in 2019, when he hit 53 home runs and broke the all-time rookie home run record that Aaron Judge of the Yankees had set in '17. Tom Seaver didn’t have a better rookie year than that. Nor did Dwight Gooden, as dazzling as he was as a teenager, in 1984. No Mets hitter, rookie or otherwise, ever had a better year at the plate. Alonso wasn’t just the National League Rookie of the Year, he was as valuable a player as there was in the league as the Mets were winning 86 games and making a late run at the postseason.

Alonso also knocked in 120 runs, played 161 games, had 597 plate appearances and posted a slash line of /260/.358/.583 for a .941 OPS. The kid from Tampa wasn’t a sure thing to even make the team when he got to Spring Training, and he then proceeded to do all that. It was one of the great and surprising New York slugging stories of all time, all the way back to Babe Ruth.

And then it seemed as if Alonso went away in the short season of 2020, and cue all the stories about the bear going into hibernation. Only he really didn’t. Now, he is about to begin his third season with a lot more help around him in the Mets' batting order, simply because of the presence of Francisco Lindor in it. Look out for Alonso in '21. And duck.

Even if there had been a full season in 2020, which there sure wasn’t, Alonso wasn’t going to hit 50 homers again. Of all the sluggers in history whose names haven’t been attached to performance-enhancing drugs, only two hit 50 homers back-to-back. Ruth did it in 1920-21. Ken Griffey Jr. did it in 1997-98 in Seattle. Mickey Mantle hit more than 50 in a season twice total. So did Willie Mays. The great Hank Aaron never hit 50. Since Judge, who’s been hurt off-and-on for three years now, hit his 52, he’s hit a total of 63 in the last three seasons.

So here is what Alonso did in the 57 games he played in 2020: He hit 16 home runs, which averages out to 45 over a 162-game season. He knocked in 35, which would have put him right around 100 in a full season. Did his slash line go down, across the board? It did. Is there any way of knowing what he might have done in 100 more games? We’ll never know. No one in baseball will ever know. His batting average was .260 in ’19 and .231 last season.

And, by the way, as a way of putting his 16 homers in the short season in context: The Major League leader in home runs was Luke Voit, over there in the Bronx with the Yankees, with 22. And in a year that many seemed to think was such a huge disappointment for Alonso, he was two home runs behind Marcell Ozuna for the NL lead. Alonso didn’t go anywhere. He just took an understandable, and predictable, step back.

All of this is why he is as much a player to watch in New York City baseball this season as anybody -- as Lindor or DJ LeMahieu, as Gerrit Cole or Jacob deGrom, as Judge or Giancarlo Stanton (another player with a 50-homer season on his resume). Put it this way: Pete Alonso was already going to a player to watch even before he was seen taking ground balls at third base (yes, third base) at Port St. Lucie the other day.

“You wait and see how he’s going to get after it,” Dennis Braun, Alonso’s coach at Plant High in Tampa, Fla., told me the other day. “I watched him work out. Trust me when I tell you he is literally going to throw himself into this season.”

The Mets' offense was built around Alonso, of course, in 2019, when it became apparent that he was not going to stop hitting home runs. They will do it again this season, even with Lindor on the team, and Michael Conforto, another young star of the team, playing for a new contract. New York has James McCann behind the plate, who hit seven home runs in 31 games for the White Sox to go with a .289 batting average last season. They have Dominic Smith, who hit 10 homers in 50 games. And they still have a base-hit machine named Jeff McNeil, who, along with hitting .329, .318 and .311 in his three years in the big leagues, hit 23 homers the last time he got to play a full season. Two years ago, J.D. Davis hit 22 homers to go with a .307 batting average. The Mets have stick.

All of this organizes itself around the 26-year-old Alonso, who has the chance to be this generation’s Mike Piazza for the New York Mets. This is no comeback season for him, because he never went away. Watch out for him, anyway. Polar Bear, loaded for bear with the New York Mets.