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8/24/2014 12:47 A.M. ET

September callups will boost pitching staff

PHOENIX -- Come Sept. 1, the Padres will add reinforcements to the roster, as Major League teams can expand their rosters from 25 to as many as 40 players.

Don't look for the Padres to add 15 players, manager Bud Black said, but the team will certainly bring players to the Major Leagues for the season's final month.

Many of them will be pitchers, Black said.

"It's a luxury to have more pitchers added to take the burden off certain guys who have been here all year and with their workloads," Black said before Saturday's game against the D-backs.

But the Padres won't add players just for the sake of adding, Black said.

"There's something to keeping a roster that's useful and can function," he said. "It [number of players added] does vary from year to year, where you are in the standings, what you're trying to achieve with the players you're expanding with, and how you're going to use them."

There are a few no-brainers who will be added to the roster, like pitchers Robbie Erlin and Joe Wieland, who will likely get starts in September. Jesse Hahn, impressive during his rookie season, will rejoin the team as well.

Chances are pitcher Matt Wisler, the team's No. 2 prospect according to MLB.com, won't join the team. For starters, Wisler won't have to be protected on the 40-man roster this winter. He'll also set a career-high in innings and the team could be inclined to shut him down when Triple-A El Paso's season is done on Sept. 1.

Left-handed reliever Frank Garces, who was optioned to Double-A San Antonio Saturday when Andrew Cashner was reinstated from the disabled list, will be back.

The team could take a look at 23-year-old right-handed reliever R.J. Alvarez, who was obtained in July from the Angels in the Huston Street deal. Alvarez doesn't have to be protected on the 40-man roster this winter, but could be a part of the team's bullpen in 2015.

Alvarez has a 1.14 ERA in 34 games between two stops in the Double-A Texas League this season with 54 strikeouts in 39 1/3 innings.

Gyorko sits out with hamstring injury

PHOENIX -- Second baseman Jedd Gyorko didn't start Saturday's game against the D-backs due to a mild left hamstring injury that he sustained Thursday against the Dodgers.

Gyorko, who made two fielding errors in Friday's 5-1 loss to the D-backs, was replaced in the lineup by Yangervis Solarte.

"It got to the point where, talking to Jedd and the training staff, we decided to give him a start off," said Padres manager Bud Black. "It's truly day to day."

"We hope he feels better quickly so we can get him back out there," Black said. "Hamstrings are tricky. With everyone, it's a little different."

Since returning from the disabled list on July 28 -- Gyorko missed 44 games with plantar fasciitis in his left foot -- he was hitting .291/.358/.488 entering Saturday with four home runs and 20 RBIs in 23 games and 86 at-bats.

Gyorko pinch-hit in the eighth inning Saturday with the bases loaded and struck out.

Worth noting

• Outfielder Carlos Quentin got a second opinion this past week on his injured left knee. Black said it confirmed the original diagnosis -- a bone bruise. The second opinion was done by Dr. Neal ElAttrache of the Kerlan-Jobe Clinic in Los Angeles.

"He's not going to be returning anytime soon," Black said. "Rest is prescribed."

Quentin hasn't played since July 26.

• First baseman Yonder Alonso, already done for the season with a right forearm strain, is probably headed down a path that will lead him to surgery, Black said.

"He's heading to that decision," Black said Saturday.

Alonso hit .240 in 84 games with seven home runs and 27 RBIs. He last played on Aug. 12 when he sustained the injury while preparing to hit. Black said the surgery would likely require a four-month recovery period.

Corey Brock is a reporter for MLB.com. Keep track of @FollowThePadres on Twitter. This story was not subject to the approval of Major League Baseball or its clubs.