Ken Rosenthal of FOXSports says the Washington Nationals could be both buyers and sellers at the trade deadline.

Nationals GM Mike Rizzo told Rosenthal that he’s under no orders to trim payroll, and he could take on salary if it meant taking on a long-term asset.

Right now the Nationals have five starters on the disabled list, including Jordan Zimmermann who is coming back from Tommy John surgery. Could the Nats make a trade for a starter come July?

Earlier this month, Houston Astros pitcher Roy Oswalt was open to waiving his no-trade clause to pitch for the Nationals.

“They’ve been playing well,” Oswalt said. “They’ve got a good offensive club. I saw where they have (Stephen) Strasburg coming up. He should make an immediate impact, especially, because no one’s seen him in the league, early. There’s always a little adjustment period there.”

Oswalt has a balance of $31 million remaining on his contract that is good through 2011 with a team option for 2012.  Could Oswalt be the long-term asset that Rizzo was talking about?