The final month of the 2019 MLB season is right around the corner, and with it comes roster expansion from 25 to 40 players.

The bulk of September call-ups consist of players who have spent the season shuffling between Triple-A and the majors—the fringe middle relievers, spot starters, utility infielders and fifth outfielders of the world.

However, at least a few top prospects always get their first taste of MLB action during this window as well.

Francisco Mejia (SD), Victor Robles (WAS), Justus Sheffield (NYY), Alex Verdugo (LAD) and Kyle Wright (ATL) were among the biggest names added to rosters last September.

Which notable prospects are set to crash the party this time around? Let's take a look.

1B Nate Lowe, Tampa Bay Rays (B/R Prospect Rank: Next 50)

Stats (AAA): .290/.416/.509, 40 XBH (16 HR), 63 RBI, 63 R

Stats (MLB): .294/.365/.510, 12 XBH (5 HR), 13 RBI, 17 R

September Role: Starting first baseman

40-Man Roster: Yes

After posting a .985 OPS with 32 doubles and 27 home runs in the upper levels of the minors during the 2018 season, Nate Lowe impressed in his first MLB action earlier this year.

Despite his solid numbers, the Tampa Bay Rays shipped Lowe back to Triple-A after they acquired Jesus Aguilar from the Milwaukee Brewers at the trade deadline.

Ji-Man Choi has seen the bulk of the playing time at first base this month, and he's hitting .218 with a .762 OPS and two home runs in 69 plate appearances.

It's easy to envision Lowe pushing Choi to the bench in September if he can pick up where he left off. At the very least, he'll provide the Rays with a big bat off the bench.

C Sean Murphy, Oakland Athletics (B/R Prospect Rank: Next 50)

Stats (Rk/AAA): .303/.396/.606, 20 XBH (11 HR), 31 RBI, 34 R

September Role: Platoon role with C Josh Phegley

40-Man Roster: Yes

The catcher position has not produced much for the Oakland Athletics this season.

Josh Phegley, Nick Hundley, Chris Herrmann, Beau Taylor and Dustin Garneau have combined to hit .238/.292/.404 for a .696 OPS that ranks 19th in the majors at the position.

That could change with the addition of Sean Murphy this September.

The 24-year-old has had a tough time staying healthy in recent years, and a torn left meniscus sidelined him earlier this season.

Since returning to action at the beginning of July, he has nine home runs in 45 plate appearances at the Triple-A level. That offensive production coupled with his highly regarded receiving skills and cannon arm could make him a key contributor down the stretch before he takes over as the primary backstop in 2020.

RHP Deivi Garcia, New York Yankees (B/R Prospect Rank: 45)

Stats (A+/AA/AAA): 107.1 IP, 4.19 ERA, 1.35 WHIP, 52 BB, 161 K

September Role: Multi-inning reliever

40-Man Roster: No

The New York Yankees moved Deivi Garcia into a relief role at Triple-A earlier this month.

Whether they did so to limit his innings or as a precursor to a September call-up remains to be seen, but either way, he looks like he's ready to make an impact.

Despite an undersized 5'9", 163-pound frame, Garcia has piled up 161 strikeouts in 107.1 innings this season while climbing two levels to Triple-A Scranton/Wilkes-Barre.

His lively mid-90s fastball and 65-grade curveball would undoubtedly play up out of the bullpen, and the club took a similar approach with Luis Severino down the stretch during the 2016 season.

As the consensus No. 1 prospect in the Yankees farm system, Garcia is a big part of the team's future, but he's capable of helping out now.

3B Ke'Bryan Hayes, Pittsburgh Pirates (B/R Prospect Rank: 35)

Stats (A-/AAA): .263/.332/.415, 42 XBH (10 HR), 55 RBI, 62 R

September Role: Starting third baseman

40-Man Roster: No

The Pittsburgh Pirates have one of the most promising third base prospects in baseball in Ke'Bryan Hayes, and it's only a matter of time before he's manning the hot corner at PNC Park.

The 22-year-old hit .353/.361/.794 with four doubles, one triple and three home runs in 36 plate appearances during spring training, and he appeared to be on the cusp of reaching the majors when the regular season began.

Instead, he's spent the entirety of 2019 at Triple-A Indianapolis, holding his own against older competition and flashing the tools that have made him such a highly regarded prospect.

While he hasn't forced the team's hand with his offensive production, he's MLB-ready defensively and would be an immediate upgrade over incumbent Colin Moran (-12 DRS, -18.9 UZR/150) from that standpoint.

He's ready for a September audition to prove he's ready for the everyday role in 2020.

RHP Brusdar Graterol, Minnesota Twins (B/R Prospect Rank: 32)

Stats (Rk/AA/AAA): 60.0 IP, 1.95 ERA, 1.00 WHIP, 23 BB, 59 K

September Role: Spot starter/multi-inning reliever

40-Man Roster: No

Earlier this month, Minnesota Twins assistant general manager Rob Antony told SKOR North that he "would not be surprised" to see top pitching prospect Brusdar Graterol in the majors before the season is over.