PHILADELPHIA -- Zack Wheeler delivered exactly the type of start the Phillies needed -- and have come to expect from their ace -- in Sunday night's 4-0 win over the Cardinals in front of a sell-out crowd of 44,225 at Citizens Bank Park.

But the Phils also know they're going to need others in the rotation to step up, especially in the coming weeks leading up to the All-Star break.

On the same day that Ranger Suárez (low back spasm) joined Zach Eflin (bruised right knee) on the 15-day injured list -- and just one day after fellow starter Kyle Gibson served up homers to four straight batters in a loss -- Wheeler tossed seven scoreless innings to help the Phillies secure a series victory. He struck out five while allowing just four hits on a season-high 108 pitches, including his two fastest of the season (98.9 and 98.6 mph).

None of that should come as any surprise at this point.

Wheeler's latest gem lowered his season ERA to 2.66 -- better than the 2.78 ERA he posted last season on his way to finishing as the runner-up in NL Cy Young Award voting. He has a 1.67 ERA over his last 12 starts. He has a ridiculous 1.62 ERA at home this season and a 1.84 ERA in night games.

"Feeling pretty good, feeling better," Wheeler said. "I got a little delayed start, so just had to work through some of the rust and get back to where I need to be. I feel like I'm there."

Combine Wheeler's dominance with Aaron Nola, who has a 1.70 ERA over his past five outings while averaging 7 1/3 innings per start, and the front end of the Phillies' rotation has become one of the team's biggest strengths.

Beyond that duo, however, things have become quite murky.

While Wheeler and Nola have combined for a 2.91 ERA this season, Philadelphia's other starters have put up a 4.60 mark. To make matters worse, Eflin hasn't yet progressed to testing his knee, and Suárez was the tentative starter for the Phillies' next game on Tuesday prior to landing on the IL.

As for the immediate future, Cristopher Sánchez will start Tuesday's game against the Nationals following Monday's rare off-day -- the first time since 1916 that the Phillies haven't played on July 4 in a full MLB season. Sánchez was initially slated to start for Triple-A Lehigh Valley on Sunday, but he was pulled back from that outing. Sánchez has been stretching out as a starter for the IronPigs, but he's topped out at 69 pitches this season.

Of course, one way to offset any potential lapses in the rotation would be to simply lean more on the offense. That would have been easier with Bryce Harper (left thumb fracture) in the lineup, but other key pieces could be hitting their stride at the right time.

Rhys Hoskins homered for the fourth time in five games on Sunday night and is hitting .341 with nine home runs and a 1.193 OPS over his last 25 games. J.T. Realmuto also went deep, crushing a key two-run shot in the sixth inning to give the Phillies some much-needed breathing room. It was Realmuto's third homer in the last eight games -- matching his total from his first 62 games this season.

"It's huge. The more guys we have in the lineup who are hot, the better off we're going to be," interim manager Rob Thomson said with a smile. "But the guys at the bottom of the lineup have been doing a nice job, too."

While the lineup would certainly benefit from more consistency over the final 12 games before the All-Star break, that's something the Phillies likely won't need to worry about with Wheeler anytime soon.

"You pretty much know what you're getting day in and day out when he's on the mound," Hoskins said of Wheeler. "He's a guy who can extend a streak while you're winning or stop a losing streak. And to have that at the top of your rotation is big."