This has been the month that John Mayberry Sr. knew would come for his son.

"I'll tell you what, I knew he had it in him," the father said Thursday from his home in Overland Park, Kan. "He has worked hard his whole life in baseball and I knew he had this drive if he just kept working at it. I knew if he made some changes that eventually he would figure things out."

A lot of people had doubts about that as recently as early June, when the Phillies optioned John Jr. back to triple-A Lehigh Valley with a .231 batting average. At 27 years old and in his seventh professional season, the son of a prolific big-league slugger had a .258 career batting average in the minor leagues and never really displayed the kind of awe-inspiring power that made his father an MVP candidate with the Kansas City Royals in the mid-'70s.

Like his father, John Jr. was a first-round draft choice. John Sr. was the sixth overall pick of the Houston Astros in 1967. John Jr. was the 19th overall pick by the Texas Rangers 28 years later. Unlike his father, John Jr. did not ascend to the big leagues at a young age. By 23, John Sr. was the Royals' starting first baseman, hitting 25 home runs and driving in 100 runs in an era when hitting 25 home runs and driving in 100 runs meant something.

John Sr. finished with 255 career home runs and was inducted into the Royals Hall of Fame in 1996 after also coaching with Toronto and Kansas City.

"No matter what kind of draft choice you were, there are going to be ups and downs in this game," the elder Mayberry said. "There are ups and downs even if you're an all-star, so the thing I always told John is that he had to stay mentally tough. A lot of this game is mental."

Still, the father said there have been plenty of times when he could hear a discouraged tone in his son's voice over the phone. As a man who played 15 seasons in the big leagues and saw his career end abruptly at the age of 33, John Sr. understood.

"That split-finger fastball can make anybody discouraged," the father said.

The discouraging moments and the difficult climb to the big leagues have made this month of August all the more special for father and son.

"Going through every different rank of the minor leagues and taking kind of the long road, it definitely makes you appreciate it more," John Jr. said.

Mayberry said his father and his family helped him most through the turbulent times.

"My dad obviously has been instrumental," he said. "I talk to him a lot about the different aspects of the game. It is one of those things where you can never be discouraged. You have to keep believing in yourself and that once you get an opportunity you'll be fine."

Unconditional love appears to be the family's motivational tool. John Sr. coached his son as a youngster and made sure he got to play against the most difficult competition. Since John Jr. has reached the professional ranks after playing college ball at Stanford, the father offers advice only when asked.

"He has his own special way of keeping me motivated and keeping me excited," John Jr. said. "It's just his personality. It's definitely not tough. He keeps things light and he keeps things fun."

John Sr. said the best thing he does for his son these days is leave him alone.

"I don't want to mess him up," he said. "He calls his mother a couple times a week. We've talked about baseball all our lives, so now I don't say too much about it. I just keep reading the box scores. He's like me. He calls when he has a good night. There's more to life than baseball."

The father, in fact, thought his son might take a different life direction when he went to Stanford. He said his wife, Janice, made sure John Jr. stayed on top of his studies.

"His mother was the educator and made sure he did his homework," John Sr. said. "I made sure he took hitting practice. I worked with him a lot as a kid because I was out of baseball. I had a pretty elite team around here. We tried to play the best competition we could. My arm is still messed up now from throwing him all those curveballs and sliders."

John Sr. said his proudest moment remains when his son graduated from Stanford.

"I kind of teared up," he said. "It's a great university and he played three years there. John worked as hard in the classroom as he did on the baseball field. I always thought he'd be a senator rather than a baseball player."

This month started with another special moment for father and son.

John Jr.'s first hit of August was a two-run, pinch-hit home run off Huston Street that tied a game against Colorado at Coors Field when the Phillies were down to their final strike.

"I remember that same matchup when John was in college," the father said. "Huston is a great pitcher, but John had an idea of what to do against him because he faced him when Huston was at Texas. John got a nice hit off him then, too, and he went up there with a little confidence."

That confidence has carried through this entire month as John Jr. has gone from the roster bubble to a key cog in manager Charlie Manuel's lineup.

The father's advice: "John still has work to do. He has to stay stabilized and remain consistent. Those are the things you have to do as a big-leaguer. They always talk about that sophomore jinx. Well, it's not a jinx. If you hurt them before, they remember and they try something different the next time."

Contact staff writer Bob Brookover
or @brookob on Twitter.