OAKLAND, Calif. – The phone rings and a familiar voice begins to talk, yet Michigan State coach Tom Izzo is still a bit surprised by the nature of the call, considering the circumstances.

Speaking in those characteristic short, choppy and speedy flurries, Zach Randolph is on a roll now. Never more than a few weeks pass without Randolph calling his former college coach to catch up on life, their families and any challenges the Memphis Grizzlies veteran forward is navigating on the court.

But this conversation is a little different.

Memphis is in the midst of a second-round slugfest against Golden State, with their playoff series tied 2-2 entering Game 5 Wednesday at Oracle Arena. Warriors forward Draymond Green, a fellow Michigan State product, is just a few days removed from clocking Memphis’ Mike Conley in the face last week in the point guard’s first game back from surgery to repair fractures near his left eye. And Green’s flailing elbow almost connected with Conley’s protective mask again in a Game 4 skirmish for the ball.

That’s elevated Green to Public Enemy No. 1 in Memphis for this series.

“When I talked to Z-Bo, the first thing he said on the phone was, ‘Man, coach, I’m so proud of Day-Day.’” Izzo said of Randolph, who referred to Green’s nickname since childhood. “I’m like, ‘Man, he’s going against you and that was your first comment?’ He goes, ‘You know, I think he got screwed in the draft, but I’m really proud of all the work he’s put in already to become the player he is right now.’”

There’s a trip to the Western Conference finals at stake between these two teams desperate for a breakthrough now that defending champion and shared nuisance San Antonio is out of the way. But there’s also a brotherly bond between Randolph and Green amid the brutal battle at the core of this series.

That matchup has reunited both players with their paternal basketball figure in Izzo, who juggled his offseason college recruiting schedule and duties taking care of his 89-year-old ill father to attend Monday’s game in Memphis. Izzo met with both Randolph and Green before that game and then watched both former pupils notch double-doubles in the Warriors 101-84 win to knot the series.

Randolph and Green played for Izzo at Michigan State a decade apart, and their matchup this postseason embodies the evolution of the power forward position in the NBA over that span of time.

Randolph’s traditional postup game has been predicated on overwhelming defenders with strength, positioning and masterful footwork. His 14 NBA seasons include two All-Star appearances, an All-NBA selection and a fifth-place ranking among active players in career double-doubles.

Green, in his third NBA season, possesses the complete skillset package of the new-age power forward –- a player who stretches the floor with 3-point range, occasionally runs the offense and defends all over the court. Green’s versatility is so extreme that he finished second for NBA Defensive Player of the Year but also has sparked the Warriors with 3-point shooting in their two wins in this series.

Randolph and Green say that beyond their areas of expertise on the court, they’re not all that different. They insist that what got them to these respective stages of their careers are the seeds planted from the same source and fertilized by Final Four runs with the Spartans under Izzo.

Draymond Green shared a few minutes with his former college coach Tom Izzo before Game 4. Noah Graham/Getty Images

The magnitude of this series makes Green even more appreciative of his matchup with Randolph.

“To play against Z-Bo in a series like this means a lot,” said Green, who is averaging 14.8 points, 8.2 rebounds and 35.5 percent 3-point shooting in this series, numbers that exceed his season averages. “It’s special, because everything means more right now. Growing up in Michigan and coming through Michigan State, we had that similar route. People questioned us and doubted us, too. You appreciate the parallels.”

Green wasn’t so appreciative of the comparisons when he first arrived at Michigan State eight years after Randolph departed following his freshman season to become the No. 19 pick in the 2001 draft. Green came to campus as the No. 36-ranked prep player in the nation, but that didn’t matter as much as something else: He was also 35 pounds overweight by Izzo’s conditioning standards.

“That’s when I started hearing a ton of Z-Bo stories; a ton of them,” Green said. “Being overweight, walking into the training room my first day, the strength and conditioning coach was like, ‘Who is this doughy boy?’ He started poking me. He was like, ‘We’ve got another Z-Bo in here; a baby Z-Bo.’ I used to get that all the time. It was nothing bad, because we both did what we had to do to drop the weight.”

In the heat of the conference semifinals, Green laughs at those memories now. Sure there were the constant battles with conditioning to get themselves in playing shape and ultimately to the NBA. But Izzo says the commonalities run much deeper than that between Randolph and Green.

“You’ve got the old-school guy and the new-school guy,” Izzo said. “But the good thing is the new-school guy hasn’t forgotten what still makes champions is what the old-school guy does, and that’s be physical and not be soft. What I like about both is they’re smash-mouth, tough guys. They’re strong characters –- tough, physical, strong IQ. They’re different players, but leading their teams with the same qualities.”

Izzo uses Randolph and Green as separate case studies for his current players pursuing NBA options. Randolph left after one year and endured adjustment struggles on the court and legal troubles off it before maturing into an elite player. Green, on the other hand, was a four-year player who came into the league with an all-around NBA skill set. Izzo shows his current team film of both Randolph and Green. He considers Green one of the best screen setters he's ever seen.

Izzo chuckles when asked if he can imagine what the trash talk is like between them in the trenches.

“Day-Day can deliver it with the best of them,” Izzo said. “Most of the time, it’s respectable. I hope he can keep his cool, because as you see once in a while, he can get crazy. Zach is more meek and mild. He just tells it like it is, like, ‘Look here. You can’t guard me. This is what I’m going to do to you.’”

"I just told him to be ready when he gets his chance. People said he wasn't going to get drafted, that his knees weren't no good. So we relate. Look at where he is now. I wish him the best, except for this series." Randolph on Green

One of their run-ins was caught by national TV cameras during Game 2 right after Green reached in for the ball and inadvertently brushed Conley against the face with a forearm. Conley was already laying on the floor, signaling for a timeout after scrambling for a loose ball. During the stoppage in play, Green approached Randolph to explain the hit wasn’t intentional.

And the banter began.

“Their whole team hopped up off the bench when the whole thing happened, like I did it on purpose,” Green said. “Zach is obviously who I’m close to on that team, and I’m not going to talk to anybody else because I don’t know them. He was honestly joking, like ‘I ain’t going to hurt your MVP point guard, so don’t hurt mine.’ At the end of the day we’re playing a game and things happen. But there’s respect.”

Randolph has nothing but respect for the way Green has blossomed so far. He remembers reaching out to Green through Izzo after Green slipped into the second round and was taken No. 35 in the 2012 draft. Randolph told Green at the time that it was a blessing in disguise because he was going to an up-and-coming team. He also told him to, “Just prove the doubters wrong, man.”

Three years later, Green is arguably the second-most valuable player on a Warriors team that won a franchise-record 67 games and led the league in offensive and defensive efficiency.

“Just seeing where he’s come from -– he’s like a little brother to me,” Randolph said. “He looks up to me and came through the struggles and worked hard. I just told him to be ready when he gets his chance. People said he wasn’t going to get drafted, that his knees weren’t no good. So we relate. Look at where he is now. I wish him the best, except for this series, because I am proud of him.”

But that pride won’t stop Randolph, 33, from doing what he does best and pounding his understudy every chance he gets. The old man is hardly taking it easy on the kid. Like Green, Randolph has raised his season production in scoring and field-goal percentage in this series and averages 18 points and 8.6 rebounds. Randolph has seen his career flash before his eyes in the first two rounds of the playoffs.

He went against former Trail Blazers teammate LaMarcus Aldridge, initially a backup power forward, who was drafted and groomed to eventually replace Randolph in Portland. And now it’s Green exchanging elbows and banging with Randolph for rebounds and precious space in the paint.

“I’m getting old, but I’m getting better though, man -- going up against all these guys that came along the path after me,” Randolph said. “I tell you what, Tim Duncan, he motivates me, man. He’s doing the same thing. That’s what motivates me. So I feel like I’m just hitting my stride around here, man.”

Either from courtside or his couch, Izzo is enjoying it every step of the way. He’s smart enough after coaching Randolph and Green to know he's better off not picking sides in this battle.

“Knowing both of them, how physical they are, I just hope they’re not beating the hell out of each other before it’s over,” Izzo said. “Day-Day doesn’t care about the style points. Neither does Zach. They just want to go out there and get the job done.”

Izzo can also count on something else, like clockwork.

Those routine phone calls with both to discuss the blow-by-blow details.