Charles LeClaire-USA TODAY Sports

The four-game series between the Pittsburgh Pirates and visiting Chicago Cubs, which continues on Tuesday, looks to be a showcase for both clubs' younger players. It certainly was in the opener on Monday.

Pirates rookies Bligh Madris, in his major league debut, and Oneil Cruz, in his season debut and third big-league game, combined for five hits and six RBIs in Pittsburgh's 12-1 rout of the Cubs.

That came on the heels of another Pittsburgh rookie, Jack Suwinski, hitting three homers, including a walk-off winner, on Sunday against the San Francisco Giants.

Both the Pirates and Cubs are staring pretty far up at .500, so they are looking hard ahead to the future.

Madris was the 12th player to make his major league debut with Pittsburgh this season, and that doesn't count Cruz.

"We've had a special group come up and contribute to the big-league club, and we're hoping to just keep doing that, doing it together and having fun," Madris said.

There will be some expected bumps for teams breaking in a lot of young players.

"We're going to do some things that are going to be frustrating," Pirates manager Derek Shelton said. "We're also going to do some things ... that are going to be really exciting. It makes you start to look at it like, OK, the plan's starting to come to fruition a little bit."

The Cubs were on the rocky side of the youth invasion in the series opener.

Caleb Kilian, making his third career start, allowed seven runs, five earned, in 2 1/3 innings.

The four Cubs slated to start on the mound in the series, including Kilian, have combined for 42 career starts. The others are Matt Swarmer (four starts), Keegan Thompson (13 starts) and Justin Steele (22 starts).

"The focus is on these young guys," veteran Chicago starter Kyle Hendricks said. "We just want to keep that winning environment, even if things don't go our way day in and day out."

The Cubs have used 15 rookies this season, 10 of them pitchers. The young arms will get a good look with Marcus Stroman, Wade Miley and Drew Smyly on the injured list.

"We're a team that can be great. It's just, we have a lot of inexperienced guys," Stroman said. "They're guys that can perform, but once you get to this level, it's finding your routine, finding your flow and everything that comes in between."

On Tuesday, in a matchup of a couple of those aforementioned inexperienced players, Chicago right-hander Swarmer (1-2, 5.23 ERA) is expected to face Pittsburgh right-hander Roansy Contreras (1-1, 3.06).

Contreras, 22, will be making his sixth start of the season, the seventh of his career. He has given up four runs in each of his past two starts while failing to finish the fifth both times.

His only career appearance against the Cubs was his big-league debut last Sept. 29. He pitched three scoreless innings and struck out four.

Swarmer, 28, lost each of his past two starts, and he tied a franchise record by yielding six homers on June 11 against the New York Yankees. In his first two starts, he became the first Cubs pitcher since Gene Lillard in 1939 to open his career with two consecutive starts going at least six innings and giving up no more than one run.

Swarmer has not faced Pittsburgh.

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