What is Zack Greinke’s legacy in Kansas City?

This evening, Zack Greinke will take the mound at Kauffman Stadium for just the fifth time since he made his last start in a Royals uniform in 2011. The soon-to-be 36-year-old is now a member of the Houston Astros, who now boast the most dominant starting rotation in baseball. Gerrit Cole and Justin Verlander are in a tug-of-war with each other and Lance Lynn, of all people, for the American League Cy Young Award. Cole and Verlander have combined for an 11.9 fWAR this season and are both top-five pitchers in baseball according to that metric.

Greinke, however, is not far behind. While he was a late addition to the Astros, added at the trade deadline in exchange for three of the Astros’ five best prospects, he ranks 12th among pitchers in fWAR with a 4.6 mark. His 2.99 ERA is his best since his ridiculous 2015 campaign, where he posted a league-best 1.66 ERA across 222.2 innings pitched.

He had the ball in Game Five of the NLDS that season, with a chance to send the Dodgers to the NLCS. He gave up three runs across 6.2 IP in a 3-2 loss to the eventual National League champion Mets, a team that would fall to the Royals in the World Series.

It’s hard to imagine what it would have been like to see Greinke take the mound in game two of the World Series instead of Jacob deGrom. His legacy in Kansas City, after all, is still complicated.

In 2010, Greinke wanted out of Kansas City. He was just two seasons into his four-year, $38 million contract and a year removed from winning the AL Cy Young Award. He asked to be traded in December after firing his agent. A source was quoted saying that Greinke “really wants to be out of K.C.”

Greinke was tired of losing, and it’s hard to blame him. In 2005, he lost a league-high 17 games. He was 60-67 in Kansas City, and the only blemish on his 2009 masterpiece was his 16 wins. This, of course, was not a real blemish on his performance. But in the history of the Junior Circuit, only two starting pitchers have won with 16 wins or fewer. One of those guys was Felix Hernandez, the silver medalist in 2009 who won the gold in 2010 with just 13 wins. The other, ironically enough, was David Cone for the Royals in 1994, who won just 16 games in a strike-shortened season.

Greinke was in the prime of his career and wanted to win. The Royals had given him little indication that they were going to win soon, having won more than 70 games just once during Greinke’s time in Kansas City.

Still, the circumstances of his departure were hard to swallow. Nobody likes the player who forces his way out of a city. But when he takes the mound tonight, Royals fans should stand and clap their hands, remembering one of the best pitchers in Royals history. Because that’s what his legacy should be, for a variety of reasons.

While his performance on the field was enigmatic, he was one of the few bright spots on some terrible Royals teams and a true Hall of Fame talent. He led Kansas City in rWAR in three of his seven seasons and his 10.4 mark in 2009 was the best in Royals history.

Now, George Brett’s 9.4 mark in 1980 would have almost certainly been higher had he played more than 117 games, and I wouldn’t argue 2009 Greinke was better. However, Greinke’s 2009 season should be viewed in the same light as Brett’s 1980 campaign. He was that good.

He was also ahead of his time. He loved analytics before it was cool, thanks in part to his former teammate and rising star coach/executive Brian Bannister. According to Bannister, he and Greinke studied James Shields and Felix Hernandez one season when Greinke became obsessed with changeups.

“He was getting into ‘pitch design’ before that was even a slang term,” Bannister told Rustin Dodd of The Athletic. In 2009, Bannister said that Greinke was pitching for fly balls instead of ground balls. He knew that fly balls were friendlier to pitchers at Kauffman Stadium and that he had David DeJesus out there, who he had the best zone rating on the team.

Greinke was doing stuff that hardly anybody else was doing at the time, stuff that has now become the currency used by teams to win championships.

We should also remember how Greinke’s story unfolded. It’s easy to forget that his career meddled from 2004-2007, as he struggled on the mound and nearly left the game due to a “nearly debilitating case of depression and constant bouts of social anxiety.”

As John Donovan wrote back in 2007, Greinke pitched through this depression during his 17-loss 2005 campaign, which deepened his “hatred of the game.” In February of 2006, he “broke down completely” in a throwing session with former Royals catcher John Buck, which led to him to miss nearly the entire 2006 season seeking psychological help.

Photo by Jeff Moffett/Icon SMI/Corbis/Icon Sportswire via Getty Images

He came back in 2007, fighting for a spot in the Royals rotation, and responded with a phenomenal four-season stretch. From 2007-2010, Greinke posted a 3.32 ERA across 150 games. During that span, he had a 19.9 fWAR, good for the 7th highest in baseball during that span.

His performance brought with it a high price tag when he requested a trade in December of 2010. In exchange for Greinke, the Royals brought in Lorenzo Cain and Alcides Escobar, half of the Core Four that helped bring a championship to Kansas City. They also got Jake Odorizzi in that deal, who would later be part of the deal that brought in James Shields and Wade Davis, the guy who closed out the 2015 World Series.

Most importantly, Greinke came of age in a sports culture that either did not understand the nuance of mental health or just didn’t care. Guys like Greinke were labeled as headcases and still are to this day. Just ask Danny Duffy. In other words, things like the NBA’s Mind Health campaign weren’t the norm when Greinke was battling behind closed doors. Few professional athletes have dealt with their mental health more publicly than him.

He has been criticized. He has been loosely compared to Rain Man by a general manager. He was hounded by Pat Neshek for an autograph and angered him when he relentlessly dodged him. All with eyes on him, the literal worst case scenario for someone with social anxiety disorder.

His story and legacy go beyond baseball, and it would be a shame if we neglected that. Did he want out of Kansas City? Sure. Was he justified in wanting out? Of course. It stung, but both sides were better for it. At the end of the day, Greinke is one of the best athletes to every play in Kansas City and he might just wind up wearing a Royals cap when he makes his way to Cooperstown.

He is perfectly unique, hilarious, and fun. There are so many amazing stories. The Alex Gordon/Jeremy Affeldt stories. “No.” The 50-MPH curveball.

So, when he takes the mound tonight, stand up and clap. Clap loud. And don’t take for granted that it might be the last time he pitches at Kauffman Stadium.