"We used to sit up in the stands, and he'd hold the radar gun," Greg said. "[Mike] would go for awhile and then he would get bored when he was younger. His mother would take him out and he'd have to go throw the ball against the wall."
If it involved a baseball or a bat, it didn't take much to keep Mike occupied while growing up in Cape Coral, Fla.
"He'd always be out in the backyard -- we had a bucket of balls, a tee and a net -- and he'd go out there and hit 100 balls every day," Greg said. "If you've ever been down to Florida in the summer, it's a little warm to do that."
Greg now works for the Reds as an area scout based in Florida.
Meanwhile, Mike is enjoying his first full year in the Major Leagues. He finished April with a .274 batting average, but it steadily fell through May, and it's been hovering near .225 so far in June. But the 23-year-old has been able to compartmentalize his woes at the plate to emerge as one of the best defensive catchers in the American League.
On Sunday at Tropicana Field, Zunino made a key block on a Felix Hernandez changeup with a man on third and the Mariners and Rays both scoreless in the seventh inning. Seattle went on to win, 5-0.
"Today my catcher was outstanding and probably saved the game for us," Mariners manager Lloyd McClendon said. "He did a tremendous job for us. Sometimes that goes unnoticed."
Ask Greg, and he'll say Mike's always been able to separate offense from defense and one pitch from the next. He's always been able to maintain a high energy level. Seeing him discouraged is as rare as a Honus Wagner rookie card, though there was one time in high school when Mike seemingly had had enough.
"It wasn't his best game," Greg recalled. "And they'd have to do the field after. I'm sitting in my chair, and he walks in and he says, 'God I hate this game.' He just walked right by and went in his room."
The next day, Mike got three hits.
"This game's pretty good!" he said after walking through the door.
Baseball ran deep in the Zunino household.
Greg played at University of California, Berkeley, before the Yankees selected him in the 31st round of 1981 Draft. He spent two seasons in the Minor Leagues, then went on to play professionally in Italy, where he met his wife Paola, a catcher for the Italian national softball team. His brother, Gary Zunino, played three seasons (1979-81) in the Minor Leagues, too.
Greg's baseball experience extends back decades -- he's worked for the Expos, Marlins and Reds -- but he took a hands-off approach while Mike tore through the ranks, earning All-State honors in 2009 during his senior year at Mariner High School in Cape Coral.
"I never really was the scout where I'd try to show him a lot," Greg said. "When he came to me and asked, 'What do you think of this swing?' or things like this, I'd help him. Until he really came to me, I'd sort of let him do his thing."
But Greg noticed the cerebral way Mike played the game and the way he asked about how to approach certain situations. When Greg helped coach his wood bat team during the fall, he let Mike call his own pitches -- something he wasn't allowed to do in high school.
"He always told me to go out there, play, have fun and trust yourself," Mike said. "That was probably the best advice he gave me."
Mike didn't sign with the Athletics in 2009 after they took him in the 29th round of the MLB First-Year Player Draft. Instead, he went to the University of Florida, where he led the Gators to the College World Series three years in a row. In 2012, Mike won the Golden Spikes Award, Johnny Bench Award and Dick Howser Trophy.
That June, the Reds, for whom Greg worked, had the 14th pick in the first round of the Draft, but there was no way Mike was slipping that far. Greg said he was thankful that the organization didn't ask him to evaluate his son, but they were going to take him if he was still available.
"Not that it would be a really low report, but we probably had the lowest grade on him, because we know where all the little flaws are," Greg said. "I'd grade him a little bit lower on the hitting. I think that's why they didn't have me do it -- because it either goes that way or the other way and you're so high on him."
When the Mariners selected Mike with the third overall pick, they knew they were getting a player who grew up around baseball. Tom McNamara, the Mariners' director of amateur scouting, had known Greg for years, and he knew Greg had passed down to his son an authentic love of the game.
"I think Mike is a sponge. You can tell by the way he plays," said McNamara. "He likes being out there. He likes to learn and he's always playing. I think he got that from his mom and dad."