NEW YORK -- For the first time, Nationals manager Manny Acta sounded like a man who had doubts that first baseman Nick Johnson could make a comeback this season.

Johnson is recovering from a broken leg, an injury which occurred on Sept. 23, 2006, at Shea Stadium. While he has made enormous progress, Johnson is not close to playing in a big league game. Right after the All-Star break, Johnson had problems with his right hip and needed a cortisone shot to get rid of the pain. Johnson resumed baseball activities late last week.

Once he is 100 percent, Johnson needs to play in rehab games, and with the Minor League season over by the first week in September, there is a good chance Johnson will not play at all this year. Johnson has taken batting practice, ground balls and run the bases, but has yet to practice his sliding.

"The only thing that worries me is the same thing that worries Nick, [which] is if the Minor League season is over before he is ready to go out there for a rehab assignment," Acta said. "Nick will need a good rehab assignment so he can have enough at-bats. If the Minor League season is over before then, it puts a big doubt in my mind.

"I really don't want to put Nick out there just for the sake of putting him in and saying that he played in 2007. If he doesn't have enough at-bats or some type of rehab assignment. ... we are just going to shut him down."

Johnson acknowledged that he is frustrated that he hasn't been able to play a big league game this year.

"I don't now how its going to progress from here until then, but I'll keep doing what I'm doing and see where we are at when it's time for me to go and hopefully play some games." he said. "It's frustrating not to get out there. It has been a grind. I will just keep pushing forward."

Trade deadline talk: The Nationals are interested in acquiring Red Sox outfielder Wily Mo Pena, according to a baseball source with knowledge of the situation. However, Washington is not willing to give up a player such as closer Chad Cordero to get Pena.

As the source put it, "[General manager] Jim [Bowden] is trying to get [Pena] cheaply."

Pena, 25, is having one of the worst years of his career, hitting .219 with five home runs and 16 RBIs. It's no secret Bowden has coveted Pena ever since he became the GM of the Nationals in late 2004. As GM of the Reds, Bowden acquired Pena from the Yankees for Drew Henson and Michael Coleman in March 2001. Back in 2005, Bowden projected Pena to be another Sammy Sosa.

If he were traded to the Nationals, Pena could solve some offensive problems. He could be the player who could carry a team for three weeks with his home runs and RBIs.

Currently, the Nationals don't have anyone who can carry the team offensively and bring victories on a regular basis. Dmitri Young is one of the league leaders in hitting, but he is not considered a power threat.

Stat of the day: Entering Saturday's action, the Nationals are 34-17 when scoring first this season.

Did you know: In their last 16 games prior to Saturday's action, the Nationals are hitting .308 (45-for-146) with runners in scoring position.

Coming up: The Nationals play the fourth game of a four-game series against the Mets on Sunday afternoon at 1:10 p.m. ET. Washington left-hander Billy Traber will face New York right-hander John Maine.