ST. LOUIS -- There was so much about that Sunday afternoon, April 7, that seemed significant. The Cardinals had just notched their first home win of the season, and Adam Wainwright, amid questions about his age and ability, had turned back the clock with the sort of performance that reassured everyone that he still had plenty left to contribute.

But it wasn’t how Wainwright led his team onto the field that day or what he did to befuddle the Padres that still sticks. Rather, it’s how he celebrated that performance, afterward, with a son.

“I went and got my little boy and I brought him into the clubhouse,” Wainwright said. “Even though he can probably barely see across the room right now -- couldn’t see hardly in front of his face probably a couple weeks ago -- it was cool to walk him through there, like, ‘Yep, yeah, this is what happens after games that you win.' I got to introduce him to everybody. That was pretty neat.”

On Thursday, he finally got the chance to introduce that little boy, Caleb Adam Wainwright, to everyone else.

Though they’ve been caring for Caleb for more than two months now, Adam and Jenny Wainwright, parents to four daughters, completed the adoption process for the boy on Thursday morning. Jenny, while at the orthodontist with one of the girls, received word from the lawyer that everything had been approved. She texted her husband, who was back home cradling Caleb and getting daughter Sadee ready for ballet.

“When I got the text that it was official, my eyes welled up all over again,” Wainwright said, speaking exclusively to MLB.com and the St. Louis Post-Dispatch on Thursday. “Even though he’s been ours for over two months already, it became real to me that a guy with four daughters, I’ve got a little boy now to call my own. It’s so special.”

The Wainwrights' adoption journey traced back about eight years, Wainwright estimated, when he and Jenny first talked loosely about the idea. But a confluence of events leading into the 2018 season convinced them it was time.

The first nudge came while the Wainwrights attended a Christian conference hosted by Pro Athletes Outreach. There, they spent time with Chad Qualls and his wife, Tara, who had been adopted when she was young. The couple had also just adopted a child of their own.

Jenny and Tara talked for hours about that process.

“Just to kind of get the ins and outs, cool factors, non-cool factors, hard things, easy things, just everything,” Wainwright said. “That kind of started us on the road talking about it a lot more.”

Then came Super Bowl Sunday.

The Wainwrights spent it, as they typically do, in Orlando, Fla., visiting with Adam's agent en route to the Cardinals’ spring complex in Jupiter. Wainwright’s agent took his company to church that Sunday for a sermon that, of all topics, centered on adoption.

Signs continued to come in more subtle ways, too. They’d see a billboard encouraging parents to consider adoption, or read a post about the blessings of the process on social media.

“You know how that kind of happens,” Wainwright said. “When you’re thinking about something in life, you just end up seeing it everywhere.”

But they still weren’t certain the timing was right, not with Adam about to begin another baseball season. A run of injuries changed that, however, and suddenly there seemed no better time than the present to initiate the process. While Wainwright nursed an elbow injury from May until September, he and his wife began preparing to expand their family once again.

First they had to make the call, something Wainwright described as “one of the hardest things in the process.” They vetted various adoption agencies and created video testimonials to introduce their family to expectant mothers. There was paperwork -- lots of paperwork -- visits from social workers and letters of recommendation from friends.

“I’m not super excited that I was hurt last year, obviously,” Wainwright said. “I had a job to do, and I wasn’t able to perform. But what it did allow us to do was to engage in this chapter of our lives.”

By September, they had become active in the adoption registry. All that was left was to wait.

It’s a wait that, for some families, can take years. For the Wainwrights, it lasted until mid-January, when they received a call that they had been selected by a mother due to give birth to a boy in Topeka, Kan., in early February.

Two days before her due date, Adam and Jenny Wainwright flew to Kansas to meet the woman and take her out to dinner. Her water broke later that night, and the baby boy arrived soon after. The Wainwrights chose to call him Caleb because of the biblical significance behind that Hebrew name. He took his new father’s name, as well.

“Caleb Adam,” Wainwright repeated out loud on Thursday. “We don’t even want to call him adopted anymore. He’s our son. He’s so special to me that I wanted him to know that. I wanted to give him my own name.”

Wainwright had only a few days to spend with Caleb before he had to return to Florida for the start of Spring Training. Jenny and their new baby boy joined him later in the month, once she had received clearance to leave Kansas. There, Caleb was smothered by his new sisters -- Baylie (12), Morgan (10), Macy (6) and Sadee (3).

“I have five mothers in there at all times who constantly fight over getting to hold him,” Wainwright joked. “There will never be a lack of love for this little dude, I promise you that.”

For most of Spring Training, Wainwright was up around 2 or 3 a.m. each night to assist with feedings. He’s involved in as much as his job will allow.

On Thursday, that meant waking with Caleb around 7 a.m. to help feed again.

“I’m looking and he’s just laughing and I’m feeding him, and I know today’s the today,” Wainwright said. “And he’s laughing, and I’m laughing. He can’t say a word yet, but he’s cooing and ooh-ing and aww-ing and all kinds of stuff, and we’re just having a full conversation. Those kinds of things, you just never forget that kind of stuff. It’s just so special.”

Wainwright was still holding Caleb hours later when that text came through to confirm that Caleb was now legally his son.

“[I] just smooched him all over,” Wainwright said. “What’s been great about it is we’ve had to just put complete faith and trust in God in knowing that this is right. This is something that we felt like we were supposed to do, and we wanted to do. [There are children that] just need parents.

“We’ve got the room. We’ve got the love. It just makes your heart warm.”