SAN DIEGO -- There is no question that the Phillies' Nick Pivetta has a tantalizing assortment of pitches. They may be on display when Philadelphia caps its three-game series with the San Diego Padres on Wednesday afternoon.

Still, Phillies manager Pete Mackanin might like to see Pivetta (4-7, 6.29 ERA) dial down his repertoire in a bid to get him back on track.

"Maybe he can use less clubs in his bag," said Mackanin, as the Phillies look to salvage the finale of the series.

At times Pivetta looks like an ace. Then there are other occasions, like his last two times out, in which the right-hander has struggled.

Against the New York Mets on Friday, Pivetta pitched 4 2/3 innings and allowed six runs (five earned) and seven hits. Versus the Colorado Rockies on Aug. 5, he worked 2 2/3 innings and was blistered for eight runs on eight hits.

Pivetta was unable to place the ball where he wanted, and that is his biggest issue, Mackanin said. Not that he is walking a ton of people -- three free passes in the two games combined -- but his aim is just a tad off.

"It's as simple as he is not commanding his pitches," Mackanin said. "He has a real nice fastball with good life, but he is just not hitting his spots. That is step one to learn how to locate that pitch. If you command that pitch, it sets everything else up."

That leads back to Pivetta's recent bullpen session with pitching coach Bob McClure.

"I think McClure might take one of his breaking balls away from him," Mackanin said. "We like his curveball; we might take his slider away from him. But it is not etched in stone, and I don't know if that is exactly what we are going to do, but it has been talked about."

There is no way to talk about the Phillies' offense without bringing up Odubel Herrera. The center fielder extended his career-high, 17-game hitting streak in the series opener Monday, but he tweaked his left hamstring in that game and didn't play Tuesday.

He is unlikely to start Wednesday when the Phillies face left-hander Clayton Richard (5-12, 5.14 ERA).

"I want to be careful with him," Mackanin said.

Richard has lost his past five decisions and is coming off consecutive no-decisions. He has never defeated the Phillies, going 0-4 with a 3.41 ERA in eight appearances, including four starts. In his lone start against Philadelphia this year, he allowed one run on five hits in six innings but did not get a decision on July 7.

Richard went six innings against the Los Angeles Dodgers in his last outing, yielding three runs on eight hits Friday. It was a back-and-forth game in which the Padres prevailed 4-3.

"These games are the fun ones, where it's close, it's back-and-forth," Richard said after the game. "They test you a little bit, make sure you're resilient through adversity."

Richard knows all about resilience, last finding the winner's circle on June 13 against the Cincinnati Reds.

Pivetta did show well against the Padres in his only career outing against them, when he opposed Richard on July 7. He went seven innings and was charged with three runs on five hits. He didn't walk a batter and struck out nine in the Phillies' 4-3 loss, with neither starter involved in the decision.

"I think he has a chance to be pretty good because he has such a lively fastball," Mackanin said of Pivetta.