NEW YORK -- Relief pitcher Alfredo Aceves threw on flat ground on Saturday for the first time since suffering a setback in his attempt to return from a bulging disk in his back.

Aceves went through his normal pitching mechanics, throwing for six to eight minutes at what he pegged at 60 percent strength.

"Nothing hurt. Everything is normal," said Aceves, who has been on the disabled list since May 12.

Aceves said he hopes to throw again on Monday, barring any discomfort.

Yankees place Thames on 15-day DL

NEW YORK -- The Yankees placed Marcus Thames on the 15-day disabled list retroactive to Saturday with a mild strain of his right hamstring. Outfielder/first baseman Chad Huffman was called up to replace Thames.

Thames said he had been coping with the injury for roughly a week, getting some extra treatment on his hamstring and trying to strengthen it in the weight room. But on Jeff Keppinger's double down the left-field line in Saturday's third inning, Thames felt effects of the injury and had difficulty bending over to field the ball. That hesitancy helped Tommy Manzella score from first on the play.

"It [stinks] because I was there to make the play and get it in, and I just couldn't bend over," Thames said.

He took his turn at the plate in the bottom of the inning, popping out to center field. Manager Joe Girardi said he noticed Thames wasn't running his hardest out of the box.

"He hit the popup to center, and when Marcus, who always plays hard, didn't run as hard as I'm used to, a real red flag went up," said Girardi.

"I felt like I was running in slow motion," Thames said, "and I'm not that slow."

Thames is hopeful that he won't require more time than the minimum 15 days on the DL. The strain is mild, and he said it doesn't feel nearly as bad as the left hamstring strain that kept him out for an even three weeks in 2007 with Detroit.

Girardi said the Yankees' trainers have not determined the grade of Thames' strain yet, and that will play into how much time he misses.

Huffman is a 25-year-old former second-round pick of the Padres who was hitting .279 this season for Triple-A Scranton/Wilkes-Barre. The Yankees claimed Huffman off waivers from San Diego in the first week of April. In 499 career Minor League games, Huffman is a .288 hitter with 65 home runs.

He was pulled before Scranton/Wilkes-Barre's game on Saturday night, receiving the good news from manager Dave Miley.

"It was a good day," Huffman said. "I drove here as fast as I could."

Huffman didn't have to wait long to make his Major League debut with the Yankees. He's in the starting lineup on Sunday in right field, batting eighth. That's a special bonus for all his family members who have made the trip to the Bronx, several of them from his hometown outside of Houston.

Posada back at catcher for Yankees

NEW YORK -- After exactly four weeks, Jorge Posada put on the catcher's gear and started behind the plate for the Yankees on Sunday against the Astros.

Posada hadn't caught a game since he suffered a hairline fracture in his right foot on a Michael Cuddyer foul tip on May 16. He had started the past 10 games at designated hitter.

"He's been excited to get back there," said manager Joe Girardi. "It's what he loves to do. When something is taken away for a while, it's hard. Players want to do what they're used to doing and accustomed to doing. ... He really misses being behind the plate."

Girardi said Posada showed a "nice little smile" when he told Posada yesterday that he would be back behind the plate Sunday. With the day off on Monday, it gives Posada plenty of time to recover for the series opener against the Phillies on Tuesday night.

"Until he catches a few games, there's always going to be that question, 'How does he come back the next day?'" said Girardi, who's more concerned about Posada's level of fatigue than he is about any setbacks with the foot.

Girardi still seems hesitant to start Posada on three consecutive days since the veteran suffered a calf injury the last time he started on back-to-back-to-back days. That said, the Yankees manager does want Posada behind the plate as much as possible.

"He's not going to DH every day. He's going to catch, and we want him to catch," Girardi said. "This is a guy who's caught multiple World Series and was the World Series catcher last year. We need him to catch for us."

Sunday will be Posada's 1,460th career game behind the plate.

All-Star voting at Stadium draws to close

NEW YORK -- With the All-Star Game just one month away, Sunday marks the final day of All-Star balloting at Yankee Stadium.

Online balloting, however, will continue at through 11:59 p.m. ET on July 1. Fans can vote online up to 25 times for their favorite players.

When the last update was released on Monday, the Yankees' Derek Jeter and Robinson Cano were leading at their respective positions. Mark Teixeira, Alex Rodriguez and Jorge Posada, though, were all stuck in second place. In the outfield, Nick Swisher, Curtis Granderson and Brett Gardner were all within shouting distance of a starting spot.

The All-Star Game is on July 13 at Angel Stadium in Anaheim.

Worth noting

Alex Rodriguez was out of the lineup for a third consecutive day. Manager Joe Girardi hopes to have him back on Tuesday against the Phillies. "My hope is that we have him on Tuesday. I can't tell you exactly what that would be, if it's as DH or possibly a full-fledged player." ... Girardi gave Nick Swisher a half-day off on Sunday, slotting him in as the designated hitter for the second time this season. Swisher went 3-for-4 in his only other start this year at DH in Baltimore on April 27. Swisher is a .300 hitter in 14 career starts at DH.... Girardi said that, with Nick Johnson still on the DL, he plans to use the DH to help rest some of his regulars. "I think it's advantageous for us," said Girardi.