SAN DIEGO -- Chris Paddack is a tall, right-handed Texan with an elite fastball/changeup mix. Naturally, he's spent time studying Michael Wacha.

"He's a guy I've made a point to watch, with mechanics, the way he pitches, pitch mix," Paddack said. "Everybody pitches differently, everybody has different techniques and mechanics. But he's one of the guys I've always watched. Being able to pitch against him tomorrow is pretty cool for me, personally."

Indeed, Paddack and Wacha will square off Saturday afternoon as Paddack looks for an encore performance to his excellent debut. Against the Giants on Sunday, Paddack threw 24 changeups. He got whiffs on 43 percent of their swings against the pitch, and he spotted it for a called strike three times as well.

Wacha's changeup is widely regarded as one of the best in the Majors. For a while, Paddack's was considered the best in the Minors by far.

Strangely enough, however, Paddack says he watched Wacha as much for the development of his curveball as anything else. Wacha, 27, doesn't use the pitch often. But it's useful. Last year, opposing hitters batted .171 against Wacha's curve (and .163 against his changeup, which he threw nearly twice as often).

Like Wacha, Paddack's curveball is clearly his third best pitch. But the Padres still think it can be an effective weapon, perhaps in the same way Wacha's is. For the most part, the Padres brush aside the notion that Paddack is a two-pitch pitcher.

"It's tough when a guy has two elite pitches,” said catcher Austin Hedges. “It might make their third or fourth pitch not seem as good. But his [curveball] is still a really good pitch."

"I've heard people say, 'It's a work in progress,'" said pitching coach Darren Balsley. "It's not a work in progress. It's a Major League curveball."

To be fair, Wacha and Paddack aren't carbon copies of each other. Their fastballs are different. Wacha's has lateral movement. Paddack's is more high-octane, and his command of the pitch might be better.

Plus, Wacha's mix is polished. He's the finished product. The 23-year-old Paddack will almost certainly evolve over time.

Still, if you like swing-and-miss changeups, Saturday's matchup is one to watch.

"When Wacha's good, he's got that changeup working, too," Hedges said. "They'll be similar pitchers when they're both on their game. I'll take our guy, though."

Noteworthy
• Matt Wisler joined the club in St. Louis after the Padres acquired the right-hander in a deal with Cincinnati earlier this week. To clear space on the roster, Phil Maton was optioned to Triple-A El Paso. Wisler is expected to serve as a hybrid middle-relief/long man at the start.

Originally a 2011 Draft pick of the Padres, Wisler, 26, was traded to Atlanta on the eve of the '15 season. At long last, he donned a Padres jersey for a big league game on Friday. He'll also finally get a chance to work with Hedges, a fellow member of that '11 Padres class.

"I told him when I got traded, 'I've actually been hoping to do this for a long time,'" Wisler said. "He was one of my favorite guys ever to throw to. Definitely excited to get back to working with him."

• Entering play Friday no National League bullpen had pitched more innings than the Padres' 29. With the sport's youngest rotation, they always expected that to be the case. It's why they added Wisler to a group that already features several multi-inning options.

"We knew we were going to ask that bullpen to throw a lot of innings early," manager Andy Green said. "They've assumed those innings well. ... At some point in time, we'll need to get some longer outings from our starters to alleviate some of that pressure. But we like the guys in our bullpen, and some of those guys throw better the more often they throw.”

Padres relievers have a 3.72 ERA through seven games with 31 strikeouts to eight walks.