PHOENIX - Freddy Galvis started the season 1 for 25 but appeared in the Phillies lineup Saturday because Ryne Sandberg wants one of his key bench pieces to find his swing. Galvis is not alone in his struggles; the Phillies bench has lacked production over the first month of games.

"I think up until now it's been adequate," Sandberg said.

The manager used his lone lefthanded reserve bat - Tony Gwynn Jr. - in the seventh inning of Friday's 5-4 loss to Arizona. Gwynn hit a possible double-play ball that was booted by Diamondbacks shortstop Cliff Pennington and let in two runs.

That meant John Mayberry Jr., who entered the game as a pinch-runner for Ryan Howard and did not make a correct read on the bases, had to hit in the ninth inning against a righthanded pitcher with the game on the line. Mayberry struck out. He is 0 for 10 with five strikeouts against righties this season.

The 30-year-old outfielder could not pinpoint the problem.

"I don't know," he said. "Just keep battling."

Darin Ruf could provide reinforcement soon. He will play in minor-league games this week as he continues to recover from a strained rib-cage muscle. Still, Ruf is righthanded, and Sandberg lacks a power threat from the left side.

"You can't have everything," Sandberg said, "but what I do like is the versatility of the guys, and that there's a lot of options there."

Joseph hurt

There is more concern for Tommy Joseph, a Phillies catching prospect, who suffered another head injury Friday at double-A Reading. Joseph was placed on the minor-league disabled list Saturday with a possible concussion.

Joseph "felt a little uncomfortable and foggy" after taking a foul tip to his head, Phillies general manager Ruben Amaro Jr. said. The 22-year-old catcher has a history of concussions and was limited to 36 games last season because of them. His future at the position is uncertain.

"Oh yeah," Amaro said. "Absolutely. We are worried about him."

Joseph started strong at Reading with four homers and an .861 OPS in 15 games.

"It's a shame because he had been really swinging the bat well," Amaro said. "He was disappointed. We're disappointed. Hopefully it won't be a long-term thing. He already felt better. We'll see."

Extra bases

Jake Diekman faced 295 batters from 2011 to 2012 and allowed two home runs. He permitted three homers, including one in Friday night's loss, over a 21-batter span this month. . . . Major League Baseball upheld the scoring on Ryan Howard's single and error from April 20, which means he remained a double shy for the cycle in that game.