The sessions would often include former Red Sox hitting coach Walt Hriniak.
Grandpa Yaz can now admit that he wasn't always the most gentle person during these tutorials.
"Sometimes, I was a little too intense," chuckled the 74-year-old Hall of Famer. "But I've learned to mellow out."
With the Orioles making the trip to Fort Myers on Sunday, it wasn't difficult for manager Buck Showalter to bring Minor League outfielder Mike Yastrzemski along as one of his "extras."
When did this idea pop into Showalter's head?
"Three months ago," Showalter said. "One, he's a good player, he's a prospect. He's been on our JIC list."
By JIC, Showalter meant "just in case." Every team has a list of such players to go on trips during the spring. And with the chance for a Yastrzemski reunion, this one made a lot of sense.
"We brought him here not because he's any kin of Carl but because he's a good player," Showalter said. "Obviously, if you're going to take him at some time, it's a nice little moment for him, and I'm not going to tell you I didn't think about it."
When Mike Yastrzemski stepped on the field at JetBlue Park on Sunday, he immediately sought out his iconic grandfather, who was behind the batting cage watching current Boston stars like Dustin Pedroia and David Ortiz prepare for the season.
This was Carl Yastrzemski's first day at camp, after arriving in Fort Myers a couple of days ago. And it was also the first chance he'd get to see his grandson play in a game since he went pro.
The Orioles selected Mike in the 14th round of the 2013 First-Year Player Draft as a left-handed-hitting prospect out of Vanderbilt.
"He didn't make it to Aberdeen, but he came down to Vandy a couple times," said Mike Yastrzemski, 23. "That was a good time."
On Sunday, Mike Yastrzemski wore No. 85, a typical number for a "JIC" player. His grandfather's No. 8 is retired on the right-field façade at Fenway.
Mike Yastrzemski entered the game as a pinch-runner in the top of the sixth. He stayed in the game and played right field, the opposite line of where his grandfather patrolled for all those years, and grounded to short to open the top of the eighth.
It wasn't quite Fenway Park, but at this point in time, Fenway South will do.
"To play at a replica of Fenway in Spring Training, and my first time being at a big league camp, [that's] real special," Mike said.
Before Miguel Cabrera won the Triple Crown in 2012, Carl Yastrzemski was baseball's last to pull off that rare feat, back in 1967.
But in many ways, Carl Yastrzemski is to Mike what any grandfather is to a grandson -- a comforting presence.
"You know, it's been great," Mike said. "It's like a normal grandfather-grandson relationship. We talk about a lot of other stuff other than just baseball -- fishing, baseball, golf. It's all good."
While hitting technique is all well and good, the thing Carl seems to respect most about his grandson is his work ethic, which clearly has stayed in the family.
"Well, it means a lot. It just proves that a lot of hard work can take you a long way," Carl said. "He's worked hard all his life. He wanted to be a player, and he put the effort and time into it."
The Red Sox did draft Mike in 2009, when he was graduating from high school.
"My thought at the time was that college was the right decision for me, and I'm happy where I am now," Mike said. "I'm still getting to play down here at the Red Sox Spring Training."
The situation seems to have worked out just right for all parties. Carl knows that his shadow could have made life tough for Mike as a Boston prospect.
"Without any doubt," Yaz said. "I think if he would have signed with the Red Sox, it would have been too much pressure. He likes the Baltimore organization. They are a great organization, Dan Duquette [is there], so he's very happy there."
Mike Yastrzemski realizes at this point of his development that his bloodlines probably aren't going to impact him positively or negatively.
"As I've grown up and gone through more baseball and the experience I've had, I realized I don't get treated any differently," Mike said. "Everyone looks at you as a baseball player rather than the name."
The advice he gets from his grandfather these days falls under the category of nurturing.
"He tells me to be myself and go out there and have fun and hit the ball hard. You can't do anything after you hit it," Mike said.
It's doubtful that he could have a batting stance quite as distinctive as the one his grandfather used, the one Little Leaguers throughout New England tried imitating back in the day.
"A little bit, except he lets go of the bat," Yaz said.
Though Carl Yastrzemski spends far more time in a fishing boat these days than at a baseball diamond, he will be following the path of his grandson.
"I think he has a shot because he has the desire and the determination," Yaz said. "That can take you a long way. Like I said, he's always worked hard, and you can't rule that out as being a big factor."