LAKELAND, Fla. -- Nate Karns' scheduled bullpen throwing on Sunday didn't happen because he developed what the club characterized as tightness in his upper right leg. The Nationals' Minor League pitcher of the year for 2012, Karns is effectively shut down until the club receives a second opinion about his problem. The tightness developed after his first spring appearance. He's had three outings totaling 3 2/3 innings.

He had been a candidate to assume Gio Gonzalez's place in the spring rotation if Gonzalez's time with the USA World Baseball Classic team was extended. Ross Ohlendorf, who has pitched eight innings in three appearances, is the other Spring Training understudy candidate for Gonzalez.

Johnson rushes home to scout Classic

LAKELAND, Fla. -- Davey Johnson was quite pleased by the brevity of his team's 2-1 loss to the Tigers on Sunday. A two-hour, 21-minute game got him on the road earlier than expected so he could return to his home in Winter Park -- not far from here -- to scout World Baseball Classic telecasts.

"I don't watch them,' Johnson said. "I scout them. You can't turn off the critical eye."

What the Nationals manager meant was he can't help but evaluate talent when he watches baseball.

Johnson had watched, er, evaluated three of the four scoreless innings thrown Saturday night by Russ Detwiler in the USA's 6-2 victory against Italy. Detwiler earned the save. Johnson, adjusting for the "spring ahead" time change, had to turn off his television after three innings, but he saw enough.

"That was a big shot in the arm for their bullpen," he said. "That's maybe my other left-hander in the 'pen. He looked great. I knew he was going to do good."