Sometimes, the Baseball Gods smile. Sometimes, circumstances align to give fans a gift. A moment that can define a season. Or a career.

Johnny Cueto’s start today is such an event.

Cueto, acquired in a trade deadline deal by Dayton Moore, was not brought to Kansas City to win a division. The Royals already had a sizable lead when Moore pulled the trigger on a trade sending three left-handers to Cincinnati. No, the Royals brought Cueto to KC for the postseason. To start in big games. For moments like these.

All postseason starts are large, but they are not all created equal. I don’t need to tell you, today is massive. This is Game Five of a best of five game series. This is the most important start of the 2015 season for the Royals and it’s the biggest game of Cueto’s career. One start. A handful of innings. That’s what will define Cueto’s tenure in the Royals starting rotation. Success or flop, it all hinges on what happens when he grips the ball and stands 60 feet and six inches from Sal Perez at little after seven o’clock on Wednesday evening.

Trades are rarely tidy. Fans and pundits alike want to pass judgement quickly, but it’s never that simple. Today, Royals fans feel great about the Zack Greinke trade (come on down Lorenzo Cain and Alcides Escobar) and the Wil Myers deal (thank you, Wade Davis) but at the time, both deals were universally panned. These things take time to resolve. The Cueto deal was not such a trade. Last July the Royals knew they needed to fortify their starting rotation heading into October. Moore explored the market, identified the best pitcher available, and made him a Royal. Moore gets massive credit for making this move. You may or may not believe in teams having windows of contention. No matter. Yet when you have opportunity, you’d better be ready to strike. The players Moore shipped to Cincinnati may develop into useful major leaguers and could provide value to the Reds for years. That won’t matter if Cueto steps up and becomes an integral part of a championship team.

The circumstances of Cueto’s arrival in Kansas City underscore just how unique this situation is. After nearly three decades of selling or inertia at the deadline, the Royals were buyers. Buyers. Because they were contenders. This is unchartered waters for Royals fans.

Then there is the reality that Cueto is a rental. He’s not a long-term Royal, nor was he ever meant to be. His is a mercenary mission. He’s a right arm for hire. A pitcher to be primed for two months before being unleashed in October. And Royals fans, who understand the economics of the game better than any fanbase, are fine with this setup. As long as Cueto delivers on his potential. It’s a potential we haven’t seen in full, so that’s why we are leery ahead of Game Five.

Sometimes, things don’t go according to plan. In 213 starts for the Reds, Cueto posted a 3.21 ERA and 21.7 fWAR. We can quibble over the meaning of the word “ace,” but there can be no debate over Cueto’s status as a top-tier starting pitcher. Cueto’s performance since he switched his Reds for Royals blue has been underwhelming. Over a stretch of five starts he allowed 30 runs in over 26 innings. Woof. It wasn’t just a bad stretch for Cueto. It was a dismal run of starts he had never experienced before. Then came the excuses: He didn’t like where Sal Perez was setting his target. He was distracted by his impending free agency. Blah, blah, blah.

Everyone assumed that Cueto would front the Royals rotation in the postseason. Their large lead would enable the team to shuffle the starters to ensure Cueto would get the baseball in Game One. Except his struggles, combined with the second half surge of Yordano Ventura, meant that Cueto would be pushed back to Game Two. And now here we are.

Honestly, none of the struggles that Cueto has endured in Royals blue matters. It didn’t matter at the time. It doesn’t matter now.

The August 10th four hit shutout against the Tigers? A nice moment, but irrelevant. The September 13 start against the Orioles where he coughed up eight runs in over six innings? Not so nice. Equally irrelevant. Those starts are meaningless because he wasn’t brought here to win or lose games in August or September. He was brought here to front the rotation in October. He was charged with leading the Royals deep into the postseason.

Calling the trade a bust or questioning Cueto’s ace status has been a premature exercise. Judgement was going to be simple and it was going to wait until October. Judgement will likely come today.

The Royals need Cueto. They paid the market rate for a top-notch starting pitcher and they need him to be on his game to get them to the ALCS. And Cueto needs the Royals. He needs this opportunity to wash away the taste of a middling stretch run that could ultimately cost him dollars on the free agent market. He needs to prove that he can be the man in the big situation.

The only thing that matters is what happens on that circular patch of dirt in the middle of The K in Game Five of the ALDS. Just like Dayton Moore drew it up back in late July.

Game on.