Pitcher Jeremy Jeffress was sent to Double-A Northwest Arkansas by the Kansas City Royals, and manager Ned Yost has replaced him on the roster with Vin Mazzaro, who was recalled from Triple-A Omaha.

According to the team's website, Yost simply needs an arm after going through a rough series against the Boston Red Sox.

Furthermore, the move allows Jeffress to be on the Double-A roster when the team's season ends, meaning that he could return to the Royals immediately without taking the 10-day delay usually required.

Jeffress has eight strikeouts and no earned runs through eight games played with Kansas City. He played in Sunday's 8-6 loss and gave up two unearned runs and walked one in two-thirds of an inning.

Mazzaro, who hasn't pitched since last Tuesday, had a 3.63 ERA in 22 games with Omaha, eight of which were starts.

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