BOSTON -- When it comes to the 2021 Red Sox, lefty Martín Pérez is the player who can be described best as the man of the people.

He sends messages to fans via Twitter before starts. He thanks them after starts -- good and bad -- for their support. And he pretty much just has a good time being part of their world, which is known as Red Sox Nation.

So maybe it is fitting that when the Red Sox get what will be their biggest crowd of the season so far on Tuesday night at Fenway Park against the Astros, Pérez will be on the mound.

Why has he gone out of his way to form such a strong connection with the fanbase in his first two seasons in Boston?

“I like for the fans to know who Martín Pérez is. It’s not just a baseball player,” Pérez said. “I just want the people and the fans to know who Martín Pérez is as a person, where I come from, what kind of things that I do. No matter what I do, if I have a good game or a bad game, I’m going to be there for my fans and I want the fans to understand that, when I don’t have a good game, I’m still going to say thank you for the support because we need that."

Though Tuesday will be the third game Fenway has been operating at full capacity, it will be the first one that fans with season-ticket packages are included in, which will make the attendance vault to what will easily be the highest of the season. Add in the fact the Astros are in town and it will make for an even more charged atmosphere.

After pitching at an empty Fenway last season, then at 12% and 25% capacity this season, Pérez will gladly take in all the volume that comes with 100% capacity.

“I’m going to enjoy that moment and show the fans what I have. That’s it,” Pérez said. “Now it’s fun because we’re going to have the fans, and we’re going to have them at 100%. I think I’m going to enjoy it a little bit more, because we’re finally going to have the support that we've been waiting for.”

This will be the first Pérez Day with a large audience. What exactly is Pérez Day?

It was just one of those quirky things that took off on social media during an otherwise depressing season for the Red Sox. Pérez’s starts became known as Pérez Day on places like Twitter and Instagram, and now you can tell what day it is by the attire in the Boston clubhouse.

“This Spring Training, a company from Canada, I think it was a [Red Sox] fan, sent me a text and said, 'We’re going to make you a shirt, a Pérez Day shirt,' and he made me a couple, and I’m just trying to give each one to my teammates, but we needed more,” said Pérez. “My teammates are telling me, 'We need more.' I called him again and he made 100 shirts and I gave it to everybody, and that’s why we have a Pérez Day in the clubhouse, but it’s really fun.

“I think it’s not just Pérez Day, it’s a Red Sox day. We come ready every night and do our best to perform and make it a great game for the people who are watching us. We’re proud to be here and do that for a lot of people. Everybody in the clubhouse -- clubbies, staff, I think our GMs, too -- wear the shirts. That’s fun. That makes me go out there and I have to [pitch well], because they really love me and I need to give that support back with my outing that day.”

These days, Pérez is worthy of team and fan support for more than just his friendly personality.

The man who entered the season as the club’s No. 5 starter has the best ERA of any member of the rotation at 3.09. This, even though he had a 5.71 ERA after four starts. In his last seven starts, Pérez is 4-1 with a 1.98 ERA.

The dramatic change in Pérez’s results have come from, well, the changeup.

“I started talking with my pitching coach and with Jason [Varitek] and [manager Alex Cora] and they told me, 'You’ve got to use your changeup a little bit more,'” said Pérez. “So I just worked on that and I started focusing a little more on my bullpens and trying to find the feeling again with that pitch.”

In his 10th season in the Majors, Pérez is trying to make this his best yet.

“Yeah, you can still learn,” said Pérez. “Every day is something new. Every day is not going to be the same. I’ll never say I know everything. I’m a humble guy. It’s not just one player or just one pitcher, I think it’s everybody and that’s why we’ve been doing good -- we’re all together on this ride.”

Because of Pérez’s always-sunny personality, perhaps people took it with a grain of salt in Spring Training when he said over and over how good he thought the Red Sox could be this season.

When it looked like they were about to hit a bump in the road when Boston lost his start on May 5 against the Tigers, Pérez doubled down.

“We’re [bleeping] good,” Pérez said, as some members of the media couldn’t help but laugh.

What prompted him to say that on Zoom?

“I say that because a lot of guys from Twitter or Instagram, they started talking about the first three games that we lost. And when I had the chance to say, 'We’re [bleeping] good,' I was going to say it,” Pérez said.

The main reason he said it is because of how strongly he believes it.

“We’re going to do good, and we’re never going to quit,” said Pérez. “Our mentality is to compete, no matter what. We have a good team, we have good players, we have good coaches. We have to do it now and we’re ready to do it now.”

The man of the people has once again spoken. And on Tuesday, he will let his pitching do the talking in front of 30,000 or so of his closest friends.