PITTSBURGH -- Earlier this year, the Pirates invited Rob Mackowiak to join their alumni group for the annual PiratesFest convention at PNC Park. He reunited with former teammates and coaches, toured the ballpark and ran into fans who recognized him and asked for autographs.

“It was awesome,” Mackowiak said. “It made for a great weekend.”

It was a great trip for the whole family, too, as Mackowiak was accompanied by his children, Garrett and Gabrielle. Born in 2007, Gabrielle didn’t see much of her father’s career -- and she hadn’t yet been born when Mackowiak played in 593 games for the Pirates from '01-05 -- so she was baffled and amused by the recognition he received in Pittsburgh.

“Dad’s usually not cool anymore,” Mackowiak said, laughing. “Dad was cool again for a couple hours that day.”

Perhaps not as cool as he was 16 years ago, however, on May 28, 2004. That was the day Mackowiak hit a walk-off grand slam in the first half of a doubleheader and a game-tying homer in the nightcap at PNC Park only hours after his wife, Jennifer, gave birth to Garrett.

“I saw people that came up with the tickets still from that day to have them signed,” former teammate Craig Wilson said. “It’s great for him that that is something that, in Pirates history, he’ll always be remembered for.”

That wonderful day began “kinda crazy” as Mackowiak, now 43 years old, recalled. The Pirates were in St. Louis the day before, and he didn’t get home from the airport until roughly 2 a.m. ET. When he arrived, Jennifer told him they had to wake up for a doctor’s appointment at 7 a.m., less than 12 hours before the start of the Bucs’ scheduled doubleheader against the Cubs.

Their child wasn’t due for another two or three weeks, but Jennifer’s ultrasound revealed that there was no amniotic fluid surrounding the baby. Doctors performed an emergency Caesarean section, and Garrett Matthew Mackowiak arrived just after 11 a.m. at Allegheny General Hospital.

Mackowiak remained by Jennifer’s side to make sure she and Garrett were doing well, watched the nurses take care of both and eventually called Pirates manager Lloyd McClendon to let him know he’d try to make it to the ballpark for the second half of the doubleheader.

“I said, 'I’ll do my best,'” Mackowiak said.

Early that afternoon, the new parents were sitting in their hospital room when Jennifer looked at Mackowiak and said, “Why don’t you just go?” He refused. She asked him again, and again he declined to leave. Not long after, Mackowiak said, their doctor told them, “Everybody’s as good as they can be, and everything’s going perfect.”

“See?” Jennifer said. “You can go.”

Still, Mackowiak hesitated to leave his wife and firstborn son. The doctor joined Jennifer in saying that everything was going well, and they could alert him if that changed. So Mackowiak called McClendon around 2:30 p.m., went home and rushed to PNC Park, arriving around 4 p.m. -- about an hour before first pitch. He gave his phone to a clubhouse attendant with specific instructions: “If this phone rings, you answer it and you come get me.”

Mackowiak received a different kind of surprise: He was in the starting lineup, batting fifth and playing third base.

“Oh my God, seriously? I’m playing?” Mackowiak said. “I was expecting to be a backup, just because your head’s not all the way there at that point.”

It might have shown early on. He was 0-for-4 with two strikeouts when he came to the plate in the ninth inning with the bases loaded, two outs and the game tied at 5. He was still wearing the blue hospital bracelet on his right wrist, because he was told he wouldn’t be allowed in to see his wife and son without it.

“That’s why you never quit, because you might come up with that opportunity later and make the best of it and nobody remembers the 0-for-4,” Mackowiak said. “They remember what you did in that one at-bat.”

That at-bat ended with Mackowiak crushing Joe Borowski’s 2-1 pitch way out to right-center field and blissfully rounding the bases. As everyone in the Pirates dugout poured out onto the field, waiting for the new dad and walk-off hero at home plate, Bucs broadcaster Greg Brown could hardly contain his own excitement: “Mack wack, tally wack, give that dog a bone! Grand slam! Hey, how ‘bout that, Garrett Mackowiak? Your dad just hit a game-winning grand slam! Unbelievable day for Rob Mackowiak!”

“You’re running down the line like, ‘Oh my God, I just did that,’” Mackowiak said. “You turn around second base, then third base, and you see everybody there waiting for you. There’s not a better feeling in the world.”

Mackowiak wasn’t in the lineup for Game 2, so he had a moment to pull himself together in the clubhouse. Already, the day had brought his first child and his first walk-off homer in a 9-5 win over the Cubs, the team he grew up rooting against as a White Sox fan from Oak Lawn, Ill. With so much to celebrate, he called Jennifer.

“Obviously the joy between us, some tears were shed. You know, you’re just happy,” Mackowiak said. “Your son being born then something like that happening, it’s unbelievable. It’s like a book.”

And that wasn’t even the last chapter.

Mackowiak returned to the dugout, expecting he’d be called upon later in the game. After getting loose in the batting cage, he entered the game in the seventh inning on a double-switch to play center field and bat ninth. The Cubs had extended their lead to two runs by the time he came to the plate with Tike Redman on first base in the ninth inning against LaTroy Hawkins.

Mackowiak, a career .259 hitter with 64 home runs in eight seasons, described himself as an aggressive hitter -- sometimes overly so. The first fastball he saw, he was going to swing at it. Hawkins’ first pitch was a fastball, and Mackowiak blasted a game-tying homer out to right-center.

“Once you hit it, the same thing -- that feeling like, ‘I can’t believe I just hit that,’” Mackowiak said. “It goes out of the park, and it’s pandemonium. You don’t even believe it yourself when you’re running around the bases.”

Wilson brought about a quick ending, launching a walk-off homer off Francis Beltran to lead off the 10th. Asked recently about that memorable day, Wilson had to be reminded that he was the one who finished Pittsburgh’s 5-4 victory.

“The only thing I remembered about the day was Mack hitting the two home runs,” Wilson said.

Seriously? No memory of his part in all that?

“No. Zero,” Wilson said, laughing. “That’s really the memory of that day. I guess you can’t write a script better than that. You have the birth of your child, then you hit two home runs in a doubleheader. No matter what else he does or did in baseball, he will always be remembered basically for that day.”

After fulfilling his postgame obligations at the ballpark and hustling home to take their dog outside, Mackowiak hurried back to the hospital. He spent the night there, exhausted after an emotional day, and he woke up to find he was the lead story on SportsCenter. His phone was flooded with calls -- some congratulating him on Garrett’s birth, some reveling in his big day on the field and a few from friends who were angry Cubs fans.

“I remember I wanted to change my number the next day. It was so crazy,” Mackowiak said, chuckling. “It was a good crazy, though. Looking back on it now, I wouldn’t change anything. It was awesome.”

The next day, Mackowiak homered again and drove in five runs in another win over the Cubs as the Pirates improved to 23-22, the latest they’d been over .500 since 1999. He still has the ball he hit for that walk-off grand slam. He stuck with the same bat he used until it broke, then he kept that, too.

Days like that were bright spots for the Pirates amid a 20-year losing streak, happy memories from a dim period in franchise history. They were also validating for Mackowiak, an overachieving 53rd-round Draft pick who spent Spring Training fielding grounders at 7 a.m. and shagging fly balls until everyone had left the field.

Mackowiak kept playing until 2009, then in '10, he finished his college degree through the University of Phoenix and landed a job with a medical sales company. He’s able to travel and work from home near Tampa, Fla., spending time with Jennifer, Garrett and Gabrielle.

As he was reliving the finest day of his career, Mackowiak was also watching Garrett take the field. The boy born that hectic morning is now a left-handed pitcher who plays some outfield for 5 Star National, a travel baseball organization. He’s about to get his driver’s license, so he is in the market for a car.

Sixteen years later, May 28 is still a day to celebrate.

“It was a weekend that you’ll never forget,” Mackowiak said. “Everything that could happen went right.”