CINCINNATI -- September is around the corner, and you know what that means for Major League Baseball: roster expansion, longer games and players you've never heard of.

The thing is, contending teams such as the Chicago Cubs aren't just trying out players for next season. The call-ups are there for a reason.

For pitchers, it's usually to mop up some innings, especially in blow outs, so the regular relievers don't have to be used. But once in a while, a team needs a high-leverage arm, and September provides a new opportunity to find one. It can happen due to a combination of factors, beginning with the notion that the league simply doesn't know the newcomer, who has obviously performed well enough in the minors to warrant a look.

Sometimes a new arm can be a major factor for a team.

"David Price was huge for us," manager Joe Maddon said. "We put him in the bullpen in Tampa Bay, and he took off for us."

Price is a good example of a pitcher who earned a spot in September that translated to the postseason. When Maddon was manager of the Rays in 2008, Price came up for five games, including one start, and produced a 1.93 ERA and 0.929 WHIP. That earned him five more games in the playoffs, including two in the World Series.

"It can happen," Maddon said. "It's just not always easy to give guys opportunities."

That brings us to the Cubs. Their bullpen has the second-best ERA in baseball, but it has also had down moments in the second half. Almost every key reliever has slumped at one point or another. Although most have rebounded nicely, lefty Justin Wilson and righty Hector Rondon are having issues currently. That's the nature of bullpens; even on contenders, they're volatile.

If a slump for any of the Cubs relievers happens in September, this could be the year a young arm emerges. As the club has stated several times this season, it has been a good one for pitching in the minor leagues. The front office hasn't had extensive meetings on the subject yet, but they will do so in the coming days. Here are a few names to watch, forgetting 40-man roster implications for the moment. Some would have to be added:

• Righty Dillon Maples: The 2011 14th-round pick has come on strong in 2017 after a pretty down campaign last season. He has compiled a 2.36 ERA and 13 saves at three different levels in the minors this season. His wipeout slider has helped him to 97 strikeouts in 61 total innings heading into Wednesday night. The Cubs have to be curious to see how that plays in the big leagues. Why wait until 2018? Maples has arguably been the biggest surprise in the system this year.

• Righty Justin Hancock: He was acquired from San Diego for Matt Szczur and has pitched at Double-A and Triple-A so far this season. Hancock has struck out 21 batters in 18 2/3 innings. Drafted in 2011, he has yet to make his major league debut. This could be the year.

• Righty Matt Carasiti: Also acquired in a midseason deal that sent lefty Zac Rosscup to Colorado, Carasiti has some major league experience, albeit without much success. Since coming to the Cubs he has appeared in 15 games, giving up eight runs in 16 innings, though his ERA with Colorado was 2.37 at Triple-A before the trade.

• Lefty Jack Leathersich: He had a forgettable performance with the Cubs earlier this season, but his numbers in the minors are very good. They include 65 strikeouts in 41 1/3 innings. The Cubs were short from the left side at the beginning of the season, but Brian Duensing has been solid, and the Cubs are hopeful that Wilson finds his groove. If not, at least they have a lefty in waiting (if he’s needed).

• Righty starter Jen-Ho Tseng: This is the most interesting starting candidate the Cubs have right now. Like Maples, he has rebounded after a down 2016. Since being promoted to Triple-A earlier this summer, he has produced a 1.67 ERA in seven starts. If he's needed to start a game in September, it would mean either the Cubs have several injuries or they really want to give a break to their frontline pitchers, including Mike Montgomery. Tseng is probably a candidate for 2018, but he is intriguing nonetheless.

There are other candidates -- such as lefty Rob Zastryzny, who's likely to return -- but these are some of the prominent arms the Cubs will be discussing in the coming days. Don't overlook their potential impact someone could have.

Price wasn't the only pitcher Maddon saw provide a boost in September. Longtime reliever Francisco Rodriguez famously burst onto the scene in 2002 with the Los Angeles Angels, where Maddon was a coach.

"With Frankie, we knew we had something," Maddon said. "Frankie's talent was over the top, and he showed it in September and then October."

Rodriguez struck out 13 of 21 batters in September without giving up a run. Then came the postseason, in which he appeared in 11 games, giving up four earned runs in 18 2/3 innings. With his help, the Angels won the World Series. Maddon is acutely aware of how an arm could emerge if there's a need this season.

"Who knows? That guy in September could actually be [reliever] Justin Wilson for us," Maddon said. "Getting him back on track would qualify just as well. We'll see how it plays out. The bullpen is OK right now."