Kansas City recalled the right-hander from Double-A Northwest Arkansas on Tuesday -- eight days after optioning Jeffress to make room for Vin Mazzaro. With the Naturals' season ending on Monday, Jeffress was eligible to return to the big league club.
This marks Jeffress' third stint with the Royals this season. In all, he's appeared in eight games, allowing two unearned runs in 6 2/3 innings. He's struck out eight and walked six.
"This year, yeah, I've liked what I've seen," Royals manager Ned Yost said. "He's making great improvements. He's much more consistent in the strike zone, which has always been something he's needed to work on. He's throwing strikes at a much higher rate with all of his pitches, which is good. His stuff is excellent. It's just been a matter of command and execution, and he's been much more consistent with that."