Gallo slugged his 19th home run on Monday in Triple-A Round Rock's extra-inning loss against Colorado Springs. The No. 7 overall prospect has gone deep four times in his past 10 games and has five homers in 20 games this month. Gallo enters the day with a .246/.381/.557 slash line through 70 games for the Express.
Pitcher to watch: Heath Fillmyer (A's No. 18), Midland vs. Frisco (7:30 p.m. ET on MiLB.TV)
Fillmyer is set to make his second start for Midland after he tossed five innings of two-run ball in his Double-A debut on July 21. The 22-year-old right-hander, Oakland's fifth-round pick in the 2014 Draft, was promoted to Midland after an excellent first half at Class A Advanced Stockton, where he posted a 3.60 ERA with 89 strikeouts in 95 innings (18 games/16 starts).
Guerrieri has been cruising of late for Double-A Montgomery, as he enters the day having completed at least seven innings in four of his past five starts. The 23-year-old right-hander has not suffered a loss in nearly two months, going 8-0 in his 10 starts since May 27. The 2011 first-rounder is 10-4 in 20 starts and he owns a 3.94 ERA and a 1.24 WHIP through 109 2/3 frames.
A winner of five of his first six starts for Pensacola, Mahle has pitched to a 2.41 ERA with 31 strikeouts over 33 2/3 innings since moving up to the Double-A level. The 21-year-old righty was excellent at Class A Advanced Daytona before being promoted, going 8-3 in 13 starts with a 2.50 ERA and a 76-17 strikeout-to-walk ratio. Between both levels, Mahle has piled up 107 strikeouts in 113 innings, during which he's limited opposing hitters to a .216 average.
Tuesday's Top 100 prospect probables
No. 11 Alex Reyes (Cardinals' No. 1), Memphis vs. Oklahoma City (8:05 p.m. ET on MiLB.TV)
No. 47 Jake Thompson (Phillies' No. 2), Lehigh Valley vs. Syracuse (6:05 p.m. ET on MiLB.TV)
No. 53 Grant Holmes (Dodgers' No. 3), Rancho Cucamonga vs. Inland Empire (10:05 p.m. ET)
No. 68 Jack Flaherty (Cardinals' No. 2), Palm Beach at Fort Myers (7:05 p.m. ET)
More top prospect probables Adalberto Mejia (Giants' No. 9), Sacramento at Reno (Triple-A) Chris Ellis (Braves' No. 12) vs. Trevor Williams (Pirates' No. 24), Gwinnett vs. Indianapolis (Triple-A) Robert Gsellman (Mets' No. 12), Las Vegas at Fresno (Triple-A)
Adam Plutko (Indians' No. 14), Columbus at Norfolk (Triple-A)
Jordan Guerrero (White Sox No. 5) vs. Max Povse (Braves' No. 25), Birmingham at Mississippi (Double-A)
Kohl Stewart (Twins' No. 6), Chattanooga vs. Tennessee (Double-A) Rob Kaminsky (Indians' No. 9), Akron vs. Richmond (Double-A) Jason Garcia (Orioles' No. 9), Bowie vs. Hartford (Double-A) Tom Eshelman (Phillies' No. 14), Reading vs. Binghamton (Double-A)
Clay Holmes (Pirates' No. 15) vs. Myles Jaye (Tigers' No. 23), Erie at Altoona (Double-A)
Chance Adams (Yankees' No. 21), Trenton at Portland (Double-A)
Alex Young (D-backs' No. 3) vs. Yency Almonte (Rockies' No. 28), Visalia vs. Modesto (Class A Advanced)
Travis Lakins (Red Sox's No. 10), Salem at Potomac (Class A Advanced)
Elniery Garcia (Phillies' No. 20), Clearwater at Daytona (Class A Advanced) Robinson Leyer (White Sox No. 22), Winston-Salem vs. Frederick (Class A Advanced) Touki Toussaint (Braves' No. 5) vs. Dario Agrazal (Pirates' No. 30), Rome vs. West Virginia (Class A) Jesus Tinoco (Rockies' No. 15), Asheville vs. Greenville (Class A)
Dakota Chalmers (A's No. 10), Vermont at Tri-City (Class A Short Season)
Juan Hillman (Indians' No. 10), Mahoning Valley vs. Connecticut (Class A Short Season)
Mike Rosenbaum is a reporter for MLB.com. Follow him on Twitter at @GoldenSombrero. This story was not subject to the approval of Major League Baseball or its clubs.