Following years of strategic tanking, the Houston Astros had the best farm system in baseball in the early to mid-2010s. A stretch of four World Series appearances (and two victories) in six seasons has depleted the Houston minor league system, as the Astros either called up or traded away their best prospects in pursuit of a title.

The Astros' farm system ranked 27th out of 30 MLB clubs coming into this season, and following the acquisition of Justin Verlander — a deal that sent away the club's top two prospects — MLB's post-trade deadline rankings have dropped Houston to dead last. The team might not have any top 100 prospects, but there are still some players at Triple-A worthy of a late-season promotion. Here are four prospects the Astros must call up in September.

4 prospects Astros must promote to roster amid September call-ups

Justin Dirden (OF)

Even following the Justin Verlander deal — which sent Drew Gilbert and Collin Barber to the Mets — the Astros farm system is ripe with talented outfielders. Justin Dirden is among the best of them. Dirden is a Major League-ready hitter who hit 24 homers and had 101 RBI plus a .301 batting average across 124 games and Double-A and Triple-A a year ago. Injuries have led to a decline this year, as the 26-year-old has 10 homers, 42 RBI, and a .236 average in just 82 contests. Still, the left-handed hitting Dirden crushes right-handed pitching, making him an ideal outfield platoon candidate at the MLB level and giving Houston yet another talented outfield bat off the bench.

Pedro Leon (OF/2B)

Another talented outfielder at the Triple-A level for the Astros, Pedro Leon leads the Sugarland Space Cowboys (fantastic name, by the way) with 103 hits and 20 home runs this year. He has already surpassed last season's totals for the Space Cowboys and it took him 17 fewer games. This is the type of improvement Houston wanted to see from Leon in his second full season at Triple-A. This extra year of experience makes him a prime candidate for a September call-up.

Misael Tamarez (RHP)

He might not have the best numbers at Triple-A this year (5.83 ERA and 48 walks in 75.2 innings), but the Astros will nonetheless see value in Tamarez's 99-MPH fastball. His most recent start was evidence of this. Tamarez went six full innings, allowing four hits and two walks, while striking out six and not allowing a run. The 23-year-old finished second in the Astros organization with 142 strikeouts last year, and while his strikeout numbers are down in 2023, the Dominican hurler pairs his fastball with a mid-80s slider and upper-80s changeup. Tamarez is easily Houston's most Major League-ready pitching prospect, and if he can continue to keep his walk numbers low, Tamarez will make an impact for the Astros in the final month of the regular season.

Shay Whitcomb (SS/2B/3B)

Whitcomb is raking this year, with 30 home runs and 87 RBI in 109 appearances across Double-A Corpus Christi and Triple-A Sugar Land. The 24-year-old takes up an aggressive approach at the plate, looking to pull pitches and hit for power. This strategy leads to gaudy power numbers but also results in a high strikeout rate. Whitcomb has 446 strikeouts in 326 career minor-league games, exceeding 130 whiffs in each of his three pro seasons. The Astros will hope they can harness Whitcomb's power and filter out the swings and misses during the club's playoff push.