SAN DIEGO -- The Padres may have two starting pitchers miss their next scheduled starts.

Dustin Moseley has been on the fence for the last few days after he dislocated his left shoulder on June 8. Aaron Harang's next start is uncertain as he deals with pain in his right foot.

"We're giving [Moseley] and Harang time, because we don't need to tell the other players [who may start in their place] yet," manager Bud Black said. "There is a possibility that we might have a starter on Monday and we might have a starter on Tuesday different from Moseley and Harang."

Black was ready to declare Moseley out of his next start, and actually did, before Moseley interrupted Black's pregame session with the media.

"You just told them that?" Moseley asked. "Why?"

"Because it's not going to happen," Black responded.

"We'll talk later, Buddy," Moseley said.

Black said that interaction was enough to delay his decision. Moseley is going to play catch Saturday, and the team should have a decision on him and Harang by Sunday, before they head out to Colorado for the first leg of their road trip.

As for Harang, his foot pain dates back to his June 4 start against the Astros. He isn't sure when or how he injured his right foot, but he's been feeling it since.

He said it didn't bother him much in Thursday's start, and X-rays and an MRI exam came back negative.

"It's in the top, and I mean, it radiates through the foot every time I hit when I go to take off running," Harang said. "It kind of sends a quick shock through my foot."

Black mentioned Wade LeBlanc from Triple-A Tucson and other Minor Leaguers as possible replacements should Moseley or Harang not be able to go. He also has Cory Leubke as an option in the Padres' bullpen.

Rizzo launches first Major League homer

SAN DIEGO -- It didn't take long for Anthony Rizzo to conquer the PETCO Park fences -- nine plate appearances, to be exact.

In the bottom of the second inning, Rizzo swung on the first pitch from Nationals starter John Lannan, a 92-mph fastball low and inside.

The result? A 378-foot bomb over the right-field wall and Rizzo's first Major League home run.

"When I hit it, yeah, I know I got it pretty good, and it got over," Rizzo said. "So I was happy. Very happy."

Rizzo has impressed the Padres with his patience and poise at the plate, and the Nationals have also come away with the same feeling after his first three games.

"It was a four-seam [fastball]," Lannan said. "I was trying to throw it away. He put a good swing on it. He hit it. He has impressed us with the way he has handled each at-bat in this series. He is going to be really good." 

Rizzo rounded the bases and got a high-five from the Padres' next batter, Nick Hundley, on his way back to the dugout. Rizzo had 16 home runs in 52 games with Triple-A Tucson before being called up by the Padres on Thursday.

After his third game, Rizzo is 3-for-7 with four walks, three strikeouts and a hit-by-pitch. His three hits are a triple off the left-center-field wall, a home run and a double down the right-field line. Though his sample size is small, Rizzo is batting .429 with a .667 on-base percentage.

"It was good to see," Padres manager Bud Black said. "He hit it to one of the biggest parts of the park, so it shows his power. And then the double down the line ... I mean, that's the thing we saw in Spring Training: all-field hitting, all-field power ... and there's pull power as well."

The home run moved the Padres within one run of the Nationals, but it was the only run San Diego scored in its 2-1 loss on Saturday.

After the game, the 21-year-old lefty was able to retrieve his first home run ball. In exchange, Rizzo offered an autographed bat and some signed baseballs.

"It's more important for my family [to get the ball back]," Rizzo said. "I'm going to probably give it to my parents. I'm really more happy for them than I am for myself."

Injured Maybin may return next week

SAN DIEGO -- Center fielder Cameron Maybin, who was placed on the disabled list with right knee inflammation retroactive to May 28, appears close to returning to the Padres.

Maybin began a rehab assignment with Triple-A Tucson Friday night. He played center field and hit leadoff, going 0-for-2 with a walk and a strikeout over five innings.

"I didn't talk to Cam," Padres manager Bud Black said. "He did fine -- 0-for-2, walk, strikeout. I think he felt fine. I didn't talk to [Tucson manager Terry Kennedy] ... but nothing went bad, put it that way."

The injury to Maybin is swelling in the bursa sac of his right knee, a closed fluid-filled sac that functions as a buffer between the tendon and the patella, or knee bone. It serves as a gliding surface to reduce friction.

If Maybin's rehab continues to progress at the rate it is, Black said he may rejoin the team in Colorado, which is the first stop in the team's upcoming nine-game road trip.

"Don't know which day though," he said. "Monday, or Tuesday or Wednesday."

Padres sign 18 draftees

SAN DIEGO -- The Padres have signed 18 of the 53 picks they selected during last week's First-Year Player Draft.

Other than the big signing of first-rounder Cory Spangenberg on Friday, the Padres have agreed to terms with Jace Peterson, a compensation-round pick and the 58th overall selection.

Peterson, a 21-year-old infielder from McNeese State, hit .335 (75-for-224) and scored 67 runs for the Cowboys in 2011. He also gives the Padres, like Spangenberg, another left-handed bat.

A rundown of the Padres' signings thus far:

• Cory Spangenberg, 2B, Indian River State College, Round 1
• Jace Peterson, SS, McNeese State, Compensation round
• Kyle Gaedele, RF, Valparaiso, Round 6
• Colin Rea, RHP, Indiana State, Round 12
• Lee Orr, RF, McNeese State, Round 13
• Greg Gonzalez, RHP, Fresno State, Round 15
• Jeremy Rodriguez, C, Cal State Bakersfield, Round 16
• Matt Stites, RHP, Missouri, Round 17
• Mike Gallic, LF, Marist College, Round 18
• Zack Kometani, 1B, University of San Diego, Round 21
• Matthew Colantonio, C, Brown University, Round 22
• Robert Eisenbach, LHP, Faulkner University, Round 23
• Paul Karmas, 1B, St. John's, Round 25
• Justin Miller, CF, Southeastern Oklahoma State, Round 30
• Clint Moore, SS, Army, Round 31
• Kyle Brule, LHP, Oklahoma Baptist, Round 32
• James Jones, LHP, Louisiana-Monroe, Round 32
• Travis Whitmore, 2B, Pittsburgh, Round 35