There is nothing much better in baseball than a Big Series, even in May. We get one this weekend between the Astros, the best team in baseball two years ago, and the Red Sox, the best team in baseball last year. We always talk a lot about the Red Sox vs. the Yankees, because it is still the best rivalry, and it’s trying to be what it was when it was at its very best back in 2003 and ‘04. But over the past couple of seasons, Red Sox vs. Astros isn’t bad, especially since they played each other in October 2017 and then again in October ’18.

The Astros got the Red Sox in four games in the 2017 American League Division Series. Then Boston got Houston in five in the last AL Championship Series, when the Astros were the defending champs and thought they had a better team than they did when they won it all. Now the Astros are loaded again, with what has looked like the deepest and most dangerous lineup in the whole sport. The Red Sox are trying to get their bearings in the AL East after losing their way at the start of this season. Now the Astros and Sox meet up again at Old Fenway for three.

And in the middle of it all, because of everything pretty great that has happened for him in baseball since the Astros released him in the spring of 2014, is J.D. Martinez, who continues to be as important a hitter as there is in baseball.

Mookie Betts absolutely earned his AL MVP Award last year. There should have been a different award for Martinez, who came to Boston as a free agent in February 2018 and began to change everything in the Red Sox batting order: For Betts, for the other guys hitting ahead of him, for the guys hitting behind him. For everybody.

Without question, Martinez came to Boston and to that batting order and was as important in the middle of it as David Ortiz had been when he was the big bat in the middle of everything for the Red Sox. So far this season, Martinez is hitting .321 with nine homers and an OPS of .940, and it feels to Red Sox fans as if he is just starting to clear his throat. He hit a home run Tuesday night against the Rockies. He hit a home run Wednesday night against the Rockies as the Red Sox had to come back on Colorado after blowing a 5-0 lead. Now he gets ready to face his old team on Friday night at Old Fenway.

What Martinez truly continues to be, five years and a couple of months after he couldn’t get on the field for the Astros in Spring Training -- 18 at-bats -- and was designated for assignment, is one of the great and wonderful reversals of fortune in modern baseball history. Sixteen years ago, the Twins released David Ortiz to sign a Rule 5 Draft shortstop named Jose Morban. You know all the history on Ortiz with the Red Sox, and the three World Series he helped them win after he got to Boston. Now Martinez has his first World Series in the books.

Jeff Luhnow, who runs baseball operations for the Astros and is one of the bright, creative minds in the game, freely admits that Houston swung and missed on Martinez. He has told me the story of sending out emails to all the other teams when the Astros were preparing to release Martine and got “crickets” as a reply. This was before Al Avila of the Tigers took a shot on J.D. Martinez because he remembered him playing college ball with his son, Alex Avila, at Nova Southeastern University in Fort Lauderdale. So Martinez ended up with the Tigers. When he faced the Astros later in Spring Training of 2014, he hit three home runs in a game.

“The rest is history,” Luhnow has said.

It is the best possible kind of history for Martinez. Since leaving Houston, Martinez has hit 180 home runs and knocked in 508. Last year with the Red Sox, he hit 43 homers and knocked in 130 runs. And just so you know, when Martinez got to the playoffs, he didn’t stop. He hit a home run in each series the Red Sox played, he knocked in 14 runs, he had five hits against the Yankees, five against the Astros, five against the Dodgers.

There are other stories like this in sports history. The Twins did cut Ortiz. A million years ago, the Pittsburgh Steelers cut Johnny Unitas, who went on to become one of the great and stories quarterbacks in pro football history. Now there is Martinez, getting ready to once again face his old team. From the sound of silence five years ago when the Astros offered him around to everybody will come a different and much louder sound on Jersey Street, Boston, this weekend. Guy got knocked down five years ago. Got up swinging. Hasn’t stopped.