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04/11/10 2:10 PM ET

Nationals activate Livan, option Mock

NEW YORK -- The Nationals selected the contract of right-hander Livan Hernandez and optioned right-hander Garrett Mock to Triple-A Syracuse on Sunday.

Hernandez started against the Mets that same day and is expected to be the fourth starter in the rotation. Because Hernandez had a Minor League contract, the team decided to start the season with eight relievers and wait to activate Hernandez until his first start.

As for Mock, he was put on the 25-man roster even though he did not pitch well in his final three Spring Training starts, including a Minor League game against the Astros. The organization told Mock nine days ago that he would be on a short leach, and the team was not afraid to call up another pitcher if he didn't perform.

Mock didn't perform well Friday against the Mets, allowing two runs in 3 1/3 innings and walking five batters. Mock claimed he had problems throwing the ball in the windy conditions at Citi Field. It was obvious, however, that his reasoning didn't go over well with the club.

Simply, the Nationals wanted Mock to get his sinker down and throw more strikes.

"This is a performance league. We need guys to perform," general manager Mike Rizzo said. "We are here to win games. Garrett has to iron out some mechanical things to allow him to throw more strikes. The bottom line is, he'll have to perform. He has to go more than 3 1/3 innings and you have to give your ballclub a chance to win. He didn't do that through the tail end of Spring Training and in his first start. We have guys who have pitched well at the end of Spring Training and pitched well to start the season."

Mock was stoic when he talked to the media about his demotion, but he sounded like a man who understood why he is being placed on the Syracuse roster.

"It's encouraging the way the team is going," Mock said. "They are not going to put up with what I did in my first game. They are going to get somebody else in here to do [the job]."

With Mock gone, the Nationals will promote left-hander Scott Olsen in time for Thursday's game against the Phillies.

Olsen didn't make the 25-man roster because the team wanted him to build arm strength after having shoulder surgery last summer. In his first start for Syracuse, Olsen pitched 6 1/3 innings and gave up four runs on eight hits. He didn't figure in the decision. While the numbers didn't look great, it appears that Olsen's fastball is back where it should be.

"[Assistant general manager] Bob Boone was there, and he said he looked really good," Rizzo said. "His stuff looked much better than his numbers. It looks like he is getting back -- healthy wise and stuff wise. That's what we were looking for."

This story was not subject to the approval of Major League Baseball or its clubs.