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5/20/2014 8:12 P.M. ET

Rivera's offense a much-needed surprise

SAN DIEGO -- Coming off of a 3-3 trip to Cincinnati and Colorado, the Padres returned home at 21-24 with a little spring in their step and their eyes on .500.

Clearly, their pitching has kept them afloat so far this season, and one short-term challenge now will be to keep that going in the absence of ace Andrew Cashner.

The bigger challenge, both short-term and long-term, has to do with the sticks, not the arms.

"We've got to continue to pitch like we are, our pitching has been fine. But we've got to score more runs to play winning baseball," manager Bud Black said. "We're pitching to where it can happen, but if we score more runs we can gain on .500 and hopefully surpass that."

One recent surprise has been catcher Rene Rivera, who mostly during his six-year career has been known for his defense. But this month, he's hitting .333/.364/.762 with two homers and six RBIs.

Black credits hitting coach Phil Plantier and assistant hitting coach Alonzo Powell for their work with Rivera, and Rivera for making the adjustments.

"He's got some power and some bat speed," Black said. "It's laying off the right-handed breaking ball that's down-and-away. It's swinging at strikes. He's more aggressive.

"It's more of an approach to staying in the middle of the field."

Cashner encouraged by test results on elbow

SAN DIEGO -- Sighs of relief were evident around Petco Park on Tuesday, even with Padres ace Andrew Cashner not listed among the club's probable starters for the next few days.

"Really, I don't think this is anything serious at all," Cashner said a day after the club announced that an MRI revealed inflammation and that "rest and rehabilitation" was prescribed.

Though the Padres do not know when Cashner will rejoin the rotation, a team that has suffered through seven Tommy John surgeries over the past two seasons is thrilled that Cashner apparently is not a candidate for No. 8.

"I think we all feel pretty good about it," manager Bud Black said of the test results.

According to Black, the test results showed "some action in the joint" and some edema, or swelling caused by excess fluid trapped in the body tissue.

Black said the MRI showed some bleeding, "which all pitchers have when they throw a baseball."

The root of the issue seems to be Cashner's slider, which he did not throw at all two starts ago against Kansas City because his elbow wasn't feeling right and he felt the pitch was stressing it.

"It may be," the cause of the injury, Black said. "The way he wraps the slider can put [stress] on the flexor muscle in the forearm.

"He wraps that slider a little quicker than you'd like to see."

"Once I get healed, I don't think it will be an issue," Cashner said.

The right-hander said he had some elbow inflammation during his freshman year of college and that it felt similar to that.

Black indicated that Cashner likely will not pick up a baseball until Saturday or Sunday at the earliest. Though nobody knows when will start next, Cashner figures that after he takes this week off and the anti-inflammatory medicine kicks in, he should know more.

"You treat the symptoms," Black said. "A lot of times, scans don't tell the whole picture. Just like looking in the mirror sometimes doesn't tell the whole truth."

Meanwhile, rookie Donn Roach is expected to start Saturday in Cashner's place. After that, with an off day May 29, the Padres can get by with a four-man rotation and will not need a fifth starter until June 3.

Quentin should avoid DL with tweaked groin

SAN DIEGO -- Though he was activated from the disabled list last week in Cincinnati, Carlos Quentin still has not been in a starting lineup for the Padres at home all season.

That record was kept intact in Tuesday's series opener against the Twins after Quentin tweaked his right groin in Colorado over the weekend.

For now, the Padres think their injury-plagued slugger will be able to avoid a trip to the disabled list.

"We're trying to keep him off of the disabled list," manager Bud Black said. "Hopefully, this is just a couple of days off from starting.

"Maybe use him in a pinch-hitting role for the next few days."

Black indicated that Quentin would not be available at all in Tuesday night's game against the Twins, but that he expected that to change Wednesday.

Smith taking advantage of more playing time

SAN DIEGO -- The emergence of Seth Smith continues. Where he mostly played against right-handers in Colorado and Oakland, he's getting more playing time in San Diego and he's taking advantage of it.

Entering Tuesday's games, Smith's .345 batting average was the highest of any qualifying outfielder in the majors. In fact, Chris Denorfia's .322 ranked seventh, making the Padres the only team in the majors with two players ranked among the top 10 leaderboard of outfielders.

As for Smith, the Padres have been able to sit back and enjoy.

"He's on a roll right now, especially over the last couple of weeks," manager Bud Black said. "Seth has the ability to hit fastballs. He's laying off breaking balls, and he has a patient approach to start with. He's not afraid to hit with two strikes."

Said bench coach Dave Roberts: "He's always hit. He's just had an opportunity to get more at-bats with [Carlos] Quentin on the disabled list, and he's risen to the occasion."

Scott Miller is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.