September is the month when clubs that are eyeing the playoffs might also start looking toward the scoreboard and the standings. But if they are not fully focused on the task in front of them every night, those clubs might see their best-laid plans thwarted by a team that won't be heading to the postseason.

Near the end of a trying year, these teams would like nothing more than to turn their opponents' October dreams into a lot of sleepless nights this winter. Here are five that could be a spoiler during the season's final few weeks.

New York Yankees (69-69)

We will talk about youth quite often in this story as these teams have begun to look toward the future. And the Yankees haven’t looked quite this young in more than 50 years; their lineup on Sunday vs. the Astros featured six players who were age 24 or younger, which was a franchise first since 1969.

The leader of this youth movement is 20-year-old top prospect Jasson Domínguez, who contributed his first two MLB homers during the club’s three-game sweep of the defending World Series champs. Meanwhile, Anthony Volpe recently became the first Yankees rookie to join the 20-homer, 20-steal club and is slugging .564 over his previous 22 games.

Plenty of veteran Yankees have been thriving lately as well. DJ LeMahieu and Gleyber Torres are on a power binge with seven and six homers, respectively, through their past 13 contests. Aaron Judge, even in an injury-marred year, still has 31 home runs and a 1.014 OPS through 84 games. Ace Gerrit Cole is making a strong case for his first Cy Young Award, and the team’s relief corps, despite some second-half stumbles, owns the best bullpen ERA in the Majors at 3.16.

After ruining the Astros’ Labor Day Weekend, the Yankees will have opportunities to impact playoff races in both leagues this month. They have a combined 10 games remaining against two AL Wild Card hopefuls, the Red Sox and Blue Jays. They will also face the Diamondbacks and the NL-Central leading Brewers for three games each at Yankee Stadium.

• The biggest 'spoilers' in MLB history

New York Mets (64-74)

Seeing both New York ballclubs play the role of spoiler this year is why, as the saying goes, you can’t predict baseball.

On the same day that Domínguez debuted, the Mets unveiled their own hyped hitting prospect in Ronny Mauricio. He made an immediate impression, hitting a pitch harder than any Met in more than two years. The 22-year-old infielder is 6-for-15 with seven hard-hit balls in his first four MLB games. He’s fitting right in with a host of teammates who are doing damage at the plate.

Pete Alonso notched his third career 40-homer season with a two-dinger performance vs. the Mariners on Sunday. Leadoff hitter Brandon Nimmo is batting .326 with a 1.019 OPS over his past 23 games. And DJ Stewart, signed to a Minor League deal in February, has been a very pleasant surprise. Since making his season debut on July 4, his 160 wRC+ ranks 15th among hitters with at least 100 plate appearances.

On the mound, Kodai Senga can make life tough for any offense. He has racked up double-digit strikeouts in each of his past two starts and has a 2.48 ERA over his previous 10 turns. He tied a season high with 12 K’s against Seattle in his most recent outing.

The Mets scored victories over a couple of the American League's top teams, the Rangers and the Mariners, last week. Beginning on Sept. 11, they will enter a 20-game, season-ending stretch that features series against four clubs in the NL Wild Card hunt: the D-backs, Reds, Marlins and Phillies. New York is 13-6 against that quartet this season.

St. Louis Cardinals (60-78)

Although the Cardinals are on pace for their most losses since 1990, they still boast a lineup that presents plenty of challenges for contending clubs. Catcher Willson Contreras has rebounded from a dreadful start to the season to register a .329/.425/.566 slash line over his past 47 games. Similarly, Lars Nootbaar's past 47 games include a .384 on-base percentage and 20 extra-base hits. And even in relatively down years, Paul Goldschmidt and Nolan Arenado remain feared, productive sluggers who can take anyone deep.

But the best bat in the Cards' lineup right now is also the youngest: 21-year-old newcomer Jordan Walker. The 6-foot-6 phenom who opened the year as St. Louis' No. 1 prospect has gone 15-for-25 with four home runs over his past seven games. He and fellow 21-year-old rookie Masyn Winn, the team's No. 1 prospect at midseason, look like a dynamic duo for the long haul.

The Cardinals might have dealt the death blow to the Padres' postseason hopes with consecutive walk-off wins last week. They will see the Padres again this month, and that's the easiest opponent by record left on St. Louis' schedule. It will visit the top team in each league, the Braves and the Orioles, during its current road trip and also face the Phillies, who hold the No. 1 NL Wild Card, later in September. The Cardinals could really leave their mark during their 13 games combined against the Brewers (seven) and Reds (six).

Pittsburgh Pirates (64-75)

Since July 29, the Pirates have compiled a 19-17 record, featuring a series win against the Phillies and a four-game split vs. the Braves. Two faces of their franchise, Ke'Bryan Hayes and Bryan Reynolds, have led the way at the plate during this successful stretch; the former enjoyed a fabulous August while the latter has 19 extra-base hits and 27 runs in his previous 37 contests.

Following a frustrating month, All-Star right-hander Mitch Keller has regained the form that got him to the Midsummer Classic. He has allowed only four earned runs across his past four starts, which include 33 strikeouts in 26 innings while throwing a fastball 86.3% of the time.

And any team is in deep trouble if it's trailing the Pirates after the seventh inning thanks to premier closer David Bednar and setup man Colin Holderman, who has limited batters to a .152 average and a .432 OPS over his last 20 appearances.

The Pirates are in the middle of a series with the Brewers and will face the team chasing them in the NL Central, the Cubs, in two weeks. That three-game series along with the Bucs' upcoming meetings with the Reds and Marlins will influence the NL Wild Card standings, too.

Los Angeles Angels (64-75)

Shohei Ohtani has already been shut down from pitching for the rest of the season due to an elbow injury, and now he is out of the Angels' lineup due to right oblique tightness. Obviously, his availability will greatly impact just how much of a spoiler Los Angeles can be over the final weeks.

But the Angels do have a handful of bright spots beyond their two-way megastar. Nolan Schanuel, the club's 2023 first-round Draft pick, has held his own at the highest level despite barely playing in the Minors prior to his Aug. 18 debut. The lefty-swinging infielder has a .439 on-base percentage and has reached successfully in each of his first 14 games. He is one of many youngsters getting a shot with the Halos at this late juncture.

Luis Rengifo was named AL Player of the Week on Tuesday and is riding a 13-game hitting streak. Plus, before his most recent start last week, left-hander Patrick Sandoval had permitted two or fewer earned runs in all but one of his past eight outings.

Two AL divisions are very much up for grabs, and the Angels will play a significant part in how everything shakes out. In the AL East, they are taking on the first-place Orioles this week and will visit the second-place Rays in a couple of weeks. Their three-game matchups against the Mariners and Rangers could also go a long way to untangling the three-team battle in the AL West.