Here are some updates from Nationals director of player development Doug Harris on a few of the players you have asked for in the comments section.
RHP Nathan Karns:
Karns, out of Texas Tech, is a 6-foot-5, 230-lb. pitcher currently in Florida for extended spring training.
"He's good," Harris said. "He is on a mound progression. He is relatively close to pitching in a ball game down there in extended spring. He hasn't had any setbacks."
Karns had a "small shoulder thing going on. Now he is just building that arm and getting him to a point where we can get him on the mound in a game," Harris said.
Outfielder Russell Moldenhauer, who was named to the 2009 College World Series all-tournament team with the Texas Longhorns:
"Moldenhauer has had some physical things that he has dealt with," Harris said. "(Moldy) is kind of a Matt Stairs type. He is a dangerous guy but we really have to grind his defense. He didn't defend in college. He was a third-round pick as a third baseman. They basically threw away his glove at Texas. We are a National League club, we got to get him to a place where he can get on the field and defend. That is the big emphasis (with him) right now is his defense."
Outfielder Rick Hughes:
"He is in extended spring training," Harris said. "He is a big, physical kid that had a long swing. He has made some nice adjustments in his swing from last season until now that has impacted some baseballs down there. He has a ways to go in other phases of his game but he is dangerous in spots."
2B Roberto Perez:
"He had a nice year for us last year," Harris said. "We tried to convert him to catcher, but really have gotten away from it as of late. It wasn't a great fit in relation to others we have in the system. He will move around a little bit, be more of that utility-type guy."