DeJong, 22, belted a solo home run in game one of Double-A Springfield's doubleheader against Arkansas on Monday, giving him 17 home runs in his first full pro season. DeJong had some swing-and-miss issues as a result of jumping directly to Double-A from Class A Peoria, but his power has translated nicely, and he's cleaned up his defense at the hot corner.
Giolito, MLBPipeline.com's No. 1 overall prospect, is set to make his second start since returning from his first big league stint, where he allowed four earned runs on eight hits in 7 2/3 innings across two starts for the Nationals. It will also be Giolito's first Triple-A start, as he was promoted directly from Double-A Harrisburg and then had a tune-up outing for Class A Hagerstown last week. Between the two Minor League levels, the 22-year-old right-hander has registered a 3.35 ERA with 76 strikeouts and 34 walks in 78 innings (15 starts).
Castellani, whom the Rockies selected in the second round in the 2014 Draft, has had mixed results this season in the hitter-friendly Class A Advanced California League, logging a 4.05 ERA over 17 starts. The 20-year-old righty has done a good job keeping the ball in the park this season, allowing six home runs over 106 2/3 frames, during which he has piled up 100 strikeouts.
The California League hasn't been as kind to Erwin, as the left-hander enters the day with a 3-10 record and a 6.53 ERA through 18 appearances (16 starts) for Stockton. Despite throwing 2 1/3 innings in relief on Sunday, Erwin, whom oppposing hitters are raking against at a .325 clip, is slated to start for the Ports. Despite his struggles, the 23-year-old has fared well against Modesto this season, posting a 2.33 ERA over 19 1/3 innings.
Tuesday's Top 100 prospect probables
No. 66 Erick Fedde (Nationals' No. 4), Potomac at Salem (7:05 p.m. ET)
No. 92 Justus Sheffield (Indians' No. 5), Lynchburg at Wilmington (11:05 a.m. ET)
No. 97 Joe Musgrove (Astros' No. 7), Fresno at Round Rock (8:05 p.m. ET on MiLB.TV)
More top prospect probables Alec Mills (Royals' No. 13), Omaha vs. Las Vegas (Triple-A) Ty Blach (Giants' No. 21), Sacramento at New Orleans (Triple-A) Brock Stewart (Dodgers' No. 26), Oklahoma City at Tacoma (Triple-A) Ryan Merritt (Indians' No. 26), Columbus vs. Louisville (Triple-A)
Josh Turley (Tigers' No. 27), Erie vs. Harrisburg (Double-A)
Tyler Eppler (Pirates' No. 28), Altoona at Hartford (Double-A) Victor Alcantara (Angels' No. 4), Arkansas at Springfield (Double-A) Marcos Diplan (Brewers' No. 19), Brevard County at Palm Beach (Class A Advanced)
Thad Lowry (White Sox No. 20), Winston-Salem vs. Myrtle Beach (Class A Advanced)
Elniery Garcia (Phillies' No. 21), Clearwater at Bradenton (Class A Advanced)
Sean Reid-Foley (Blue Jays' No. 3), Dunedin vs. Charlotte (Class A Advanced)
Josh Sborz (Dodgers' No. 18), Rancho Cucamonga vs. Lancaster (Class A Advanced)
Triston McKenzie (Indians' No. 6), Mahoning Valley at Auburn (Class A Short Season)
Bryan Hudson (Cubs' No. 13), Eugene vs. Hillsboro (Class A Short Season)
Drew Finley (Yankees' No. 15), Staten Island at Aberdeen (Class A Short Season)
Tyler Phillips (Rangers' No. 29), Spokane vs. Vancouver (Class A Short Season)
Antonio Santillan (Reds' No. 17), Billings vs. Orem (Rookie)
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.