If any player thought suiting up for a game would be tough, that thought was quickly rendered moot when they witnessed McGregor's four children step to a podium at home plate and deliver tributes to their father, who was just 48 when he died while on a business trip.
Smith dealt with his emotion the best way he knew how -- with his third and fourth home runs of the season in the Rockies' 8-4 victory over the Marlins.
"There were a lot of built-up emotions inside of me," said Smith, whose solo shot in the second inning and three-run homer in the fourth came off Marlins starter Scott Volstad (1-2). "It was definitely exciting for me to give back a little bit, and run around those bases and get a little bit of that off of me. I had a heavy heart going into the game. My heart goes out to their family.
"Watching his family, his three daughters and son on the stage today, talking about what a great father he was, people talking about what a great husband he was, how all of the people with the Rockies talk about how great of a president he was."
The victory -- which also featured Miguel Olivo's team-high fifth homer of the year, a two-run shot -- pushed the Rockies above .500 (10-9) and gave them a series victory over the Marlins. The Rockies welcome an opportunity to move forward after the emotional time they've experienced.
"When I woke up this morning, I really was asking myself how I was going to be able to lead this club through this day -- I really was," said Rockies manager Jim Tracy. "And I watched the four McGregor children do what they did today, and we had all the strength in the world. It's as simple as that.
"I witnessed those four children, along with their mother [Lori], and I'm very, very glad today turned out the way that it did."
Marlins manager Fredi Gonzalez witnessed a pregame ceremony that culminated in the McGregor family participating in first-pitch ceremonies, with players and club employees lining the first- and third-base lines.
Even after the loss, Gonzalez was moved, saying the lesson was always to tell people you love how you feel about them. He said he wished he knew McGregor.
"I feel bad, I used to run into him in the weight room," Gonzalez said. "I never had a conversation with him."
Smith had struggled for much of this season. He entered Sunday with a .194 batting average, but it was time for him to find his groove.
The Rockies placed regular right fielder Brad Hawpe on the 15-day disabled list Sunday with a strained left quadriceps. That means Smith, who broke in as a pinch-hitter in 2007 but has started on and off since, will be depended upon increasingly.
On Sunday, Smith started in left field. Regular left fielder Carlos Gonzalez (1-for-5) moved to right, and Dexter Fowler (2-for-4 with a triple) stayed in his customary center-field spot.
"It was great to see Smith break out," Tracy said. "We've been waiting for that. We knew it was going to happen. It was just a matter of when."
Volstad was upset with his pitch on Smith's three-run homer, which gave the Rockies a 4-0 lead.
"It was a changeup that I babied in there," Volstad said. "It was like a batting practice fastball."
An almost perfect day ended with one potential drawback, however. Left-hander Jorge De La Rosa (3-1) went just five innings and lost his fastball for his final three frames because of a bone bruise on the middle finger of his throwing hand.
De La Rosa pitched scoreless ball until giving up two runs in the fifth. He gave up four hits and walked three, but managed six strikeouts to bring his season total to a club-leading 26 -- one ahead of ace Ubaldo Jimenez.
Even De La Rosa, who is 19-4 since June 1 and has the most wins of any Major League pitcher in that span, is unsure what this means for his next scheduled start.
"It was just sore," De La Rosa said. "But my arm feels good. I'll just have to wait."
Still, it was as good an ending the Rockies could have expected after a difficult day.
"It's very tough, anytime you lose a person that I hold up there with people that I've met," said shortstop Troy Tulowitzki, who walked twice, doubled and scored twice.
Thomas Harding is a reporter for MLB.com. Joe Frisaro contributed to this story. This story was not subject to the approval of Major League Baseball or its clubs.