As the Royals get closer to clinching a playoff spot for the second consecutive year, there is rising concern about one glaring weakness that's rearing its ugly head once again.

The starting rotation. More specifically, their No. 4 starter.

Johnny Cueto hasn't lived up to expectations since arriving in KC, in fact, he's been downright awful. Yordano Ventura continues to be inconsistent, and Edinson Volquez has struggled as of late. Regardless, these are the Royals' top three starters heading into the postseason. But what about the fourth man in the playoff rotation?

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The guys at Kings of Kauffman took a look at who could fill that role once the postseason begins in October:

-- Kris Medlen may be the best option in terms of results this season, but he's only about a year and a half removed from his second Tommy John Surgery. The Royals would need to balance the short term against the long term.

-- If given another major-league start, Danny Duffy could find his groove and pitch his way into the Royals' postseason plans.

-- With Danny Duffy struggling, Jeremy Guthrie has found himself back in the starting rotation. He has a level of trust with Yost and is seemingly able to raise his game when it matters most.

-- While Chris Young's time in the rotation lasted for only three months, he lost his spot in the rotation due to the improved health of the expected starters, not through ineffectiveness. If Duffy and Guthrie fail to impress, Yost could give Young serious consideration.

(h/t Kings of Kauffman)