"Tom Glavine is the strongest minded individual I've ever seen pitch," Mazzone said. "I've seen him throw shutouts with two pitches. I've seen him throw games where he'd win and strike out 10 or win and strike out none. He had the most consistent work ethic, as far as what he did between starts, and threw more often than any other pitcher I've coached in my career."
That's high praise for Mazzone, who counsels his pitchers to throw twice between starts in an era in which most coaches have their charges throw once on the side. The practice is designed to make arms stronger and more resilient, and Glavine -- who has made at least 25 starts in every season since 1998 -- is the picture-perfect example of its success.
When Mazzone looks upon the litany of successes in Glavine's career -- 10 All-Star selections, two Cy Young Awards, a World Series MVP Award and five seasons with 20 wins or more -- he sees one common trait binding them together. Nobody was willing to outwork the former second-round draft pick, who has logged more than 4,000 innings and 650 starts in the last 21 seasons.
They may do their jobs in different places now -- Mazzone with the Baltimore Orioles and Glavine with the New York Mets -- but both men can look back on the origins of their success with the Atlanta Braves.
"Sometimes they'd time his side sessions, and he broke a record one day when he couldn't get his changeup going," Mazzone said. "He stayed down there for about 20 minutes, but he'd come out the next day and throw again. And then he'd go throw in the outfield the day before he pitched and throw in the outfield the day after he pitched.
"There wasn't a day went by that he didn't have a baseball in his hand."
Sometimes that meant pitching in less than perfect health. When his turn came up, Glavine would take the ball regardless of how he felt -- but he'd do so with conviction. Most players are taught to be as careful as possible with their arms, but Mazzone said if Glavine was physically capable of taking the ball, it was nearly impossible to take it from him.
"He pitched hurt a lot. Spurs in his shoulder, elbow, everything," Mazzone said. "I know he went to the post when he wasn't feeling good, but the thing that separates him from a lot of other pitchers is he still expected to win. A lot of other pitchers go to the post not feeling good and that's their excuse to lose. That's what separates mediocrity from excellence."
Glavine didn't have his first 20-win season until 1991, which coincidentally was Mazzone's first full season as a big-league pitching coach. The seeds for that season were sewn in September 1990, when Atlanta was finishing off a last-place season. Mazzone said Glavine went 4-0 that September and started to shed the memory of a 17-loss season in 1988.
"I had him in the instructional league when he signed -- myself and Johnny Sain -- and he had that same makeup and that same Iceman mentality back then," Mazzone said of Glavine's legendary composure. "That's him. But it really kicked in in September of 1990, but it went unnoticed because we were in last place. As you know, the rest is history after that."
Glavine went on to win 20 games in three straight seasons -- a feat that hasn't been equaled since -- and helped form one of the greatest pitching staffs the game has ever seen. Together with Greg Maddux and John Smoltz, who have more than 500 wins between them, the Braves dominated the National League for more than a decade.
Smoltz is the only one of the group that hasn't left Atlanta, and he and Glavine were there long before Maddux arrived. If you discount the 1994 strike season, the Braves won 14 straight division titles -- eight of them with Glavine, Maddux and Smoltz. Mazzone, who has a tattoo that reads "14 straight" on his biceps, said the Hall-of-Fame trio taught each other quite a bit.
"They talked about the game a lot, but you have to remember Tommy and Smoltzie were together longer than that," he said. "We all learned a lot when Maddux came in, but Tommy was at the top of his game. He had already won a Cy Young, and Smoltzie was on the move to greatness. You add Maddux to the equation, and that just took everything from excellent to superhuman. That meant no more losing streaks."
Only 22 pitchers have been able to win 300 games, and Mazzone said Glavine may be one of the last. Pitchers don't get as many opportunities to throw with the five-man rotation, and with the increasing reliance on bullpens, they don't get as many chances to work deep in the game. While Randy Johnson has 284 wins, the next pitcher closest to 300 is more than 50 wins away.
Despite the milestone, Glavine's 300th win won't be his most memorable. Mazzone said that honor decisively belongs to Game 6 of the 1995 World Series, when Glavine had a no-hitter for five innings and settled for eight innings of one-hit ball in a 1-0 win. More than the success, Mazzone remembers a fiery Glavine coming into the dugout and all but issuing a guarantee.
The southpaw -- normally soft spoken -- asked for somebody to score a run, because he knew Cleveland couldn't.
"That was very out of character for him. I always told Tommy, 'You've got that stoic figure out on the mound -- that never-give-in attitude.' That sticks out, just because of what he said," Mazzone said. "It's hard to say he's blue collar. People are going to say, 'He's in the big leagues. How can he be blue collar?' But he is. There's not enough adjectives to describe Tom Glavine, the pitcher, and Tom Glavine, the person. It was a privilege to be his coach. We had a lot of fun."
Spencer Fordin is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.