Cincinnati Reds ace Johnny Cueto is headed to the Kansas City Royals.

The two teams had agreed to a trade on Saturday, before Cueto’s start against the Colorado Rockies on Saturday night, but the deal fell through because one of the Royals’ players medicals didn’t check out. Discussions continued through the night, and the two sides finally reached an agreement on Sunday morning.

Source: #Royals getting Cueto.

— Ken Rosenthal (@Ken_Rosenthal) July 26, 2015

The biggest weakness of the entire Royals roster this season has been the starting pitching. Currently, the Royals rank 22nd in MLB in starters’ ERA with a 4.30. Yordano Ventura was expected to be the ace of the staff, but he’s struggled mightily, and was even sent down to Triple-A for a day.

The lowest ERA on the staff belongs to Edinson Volquez, who has a 3.15, but after him, it’s Chris Young, who has a 3.96. Ventura and Jeremy Guthrie both have ERA’s above 5.00.

While the Royals enter Sunday’s action with the best record in the American League, 58-38, the team would’ve had a tough time in the playoffs with the rotation staying status quo. With Cueto in tow, the Royals finally have an ace that will make a significant difference in the team’s playoff success.

During the Royals’ remarkable playoff run last season, manager Ned Yost had the same problem. He ended up using his bullpen extensively in the playoffs, and that could’ve been the difference between winning the World Series, and losing in seven games to the San Francisco Giants as they did. Cueto should be able to take some of that pressure off of the Royals’ outstanding bullpen, which will allow those guys to be fresh for the games not started by Cueto.

The best team in the American League got significantly better, which means trouble for every other team in baseball.

Jason Fletcher is a Senior Writer for www.RantSports.com. Follow him on Twitter @JasonFletcher25, “Like” him on Facebook, or add him to your network on Google+.