"This is just precautionary. He's 28 years old. We are not really concerned about it. But like Patterson, let's get the forearm completely healthy and then go back out there. This is not a major setback. If he progressed after one start, it wouldn't hurt him to make one start on a rehab assignment and then go [pitch in a Major League Game]," Bowden said.
As for Patterson, he made his fifth start of the season Friday against the Orioles, his first since April 21 against the Braves. Patterson has missed two months because of a right forearm strain.
Injury report: First baseman Nick Johnson took 20 swings in the batting cage and said the lower back is feeling much better. He hopes to play against the Orioles on Saturday, but manager Frank Robinson said Johnson most likely will not see action until Tuesday against the Blue Jays.
Right-hander Pedro Astacio has yet to play in a regular-season game because of a right forearm strain, and had a setback a few weeks ago. According to Bowden, Astacio will pitch in a rehab assignment, which is coming to an end, but the Nationals could ask for an extension.
If Astacio were healthy and ready to pitch, it would be rough for him to make it into the rotation because Shawn Hill and Mike O'Connor have already established themselves.
Trade bait: The Nationals have not been getting the production from Jose Guillen, Jose Vidro, Livan Hernandez and Ramon Ortiz -- four guys needed to get the prospects the Nationals want. But Bowden didn't seem concerned about his veteran players.
Guillen is hitting .220, while Vidro is in a 4-for-24 slump. Hernandez has given up 11 earned runs in his last 8 1/3 innings, while Ortiz has given up 10 runs in his last 11 innings.
"We are playing 162 games. We all get hot and we get cold. Our players have a lot of value," Bowden said.
No help in center: While they are not getting any offensive production from Marlon Byrd and Damian Jackson, the Nationals don't have anybody in the Minor Leagues who could help at the big-league level. Bowden said that Justin Maxwell is doing OK, but he is not going to be called up from rookie ball.
"I think we have been very disappointed in our production in center field at Triple-A, at the big-league level, at Double-A, High A, Low A. Do we have anyone in our system now that is performing at a level who can improve our situation in the big leagues? No," Bowden said. "Don't go hitting .212 in Triple-A and .250 in Double-A, and tell me you are going to hit better than what our guys are doing in the big leagues."
Center fielder Alex Escobar, who is on the DL because of a strained left hamstring, is playing extended spring games, but he is not 100 percent.
Sign here: The Nationals agreed to terms with right-hander Colton Willems, the 22nd-overall selection in the 2006 First-Year Player Draft, on Friday. Willems signed for $1.425 million.
"Negotiations were tough and long, but I give [agent] Mark Rogers credit, We got it done today," Bowden said.
Willems went 7-1 with a 0.68 ERA and fanned 99 batters in 51 1/3 innings this season for John Carroll Catholic (Fla.) High.
The Nationals are trying to sign their first pick, third baseman Chris Marrero, but his adviser is in Mexico, and the Nationals are having a tough time communicating with him.
"I talked to Chris directly and I said, 'The Gulf Coast League has played three games and you should be out there playing.' He said he had goosebumps when [Ryan] Zimmerman hit the home run against the Yankees and I said, 'That could be you in three and a half years, but it can't be you in three and a half years if you sit at home.'"
The Nationals also agreed to terms with catcher Sean Rooney, the club's eighth-round selection in the draft. Washington has now agreed to terms with 20 players from their 2006 First-Year Player Draft.
Pitching change: Right-hander Ramon Ortiz was scheduled to pitch
against the Orioles on Saturday, but he was pushed back until Tuesday
against the Blue Jays. He will come out of the bullpen on Friday and
Ortiz did not go to the series against the Red Sox in order to be with his
ailing wife in New York. He returned to the team on Friday, but Robinson
felt Ortiz needed more time to get ready for his next start. Ortiz said he
was OK with Robinson's decision.
Send in your questions: The Nationals mailbag runs every Monday. Send in your questions now.
Stats of the day: Entering Friday's action, the Nationals' starters are 1-7 with a 7.27 ERA.
Since the inception of Interleague Play in 1997, the Nationals/Expos' designated hitters are hitting .228 (71-for-312) with 10 home runs and 28 RBIs entering Friday's action.
Did you know? The last time a Washington-based team took a series from the Orioles was back in 1965, when the Senators took 10 out of 18 games.
Coming up: The Nationals play the second game of a three-game series against the Orioles at 4:35 p.m. ET on Saturday.
Mike O'Connor will get the start for Washington, while left-hander Adam Loewen gets the nod for the Orioles.