Thompson, 23, has six homers this season and a pair of two-homer games in his career after his impressive 3-for-3 game on Sunday. The third baseman hit a solo homer in the fourth and a two-run blast in the eighth and is 4-for-6 over the past two games, bumping his season average up to .245 through 61 games.
Meanwhile, Flexen is new to the Double-A level, but the inexperience doesn't seem to be hindering the 22-year-old righty.
After posting a 2.13 ERA through three starts with Class A Advanced St. Lucie this season, Flexen was promoted to the Rumble Ponies, where he has gone 2-1 with a 1.74 ERA through three starts. Flexen has pitched into the seventh inning in each of those three outings and has recorded a quality start in all three.
Other top prospect performances from Sunday's action:
• No. 42 overall prospect Nick Gordon (Twins' No. 1) extended his hitting streak to 12 games with a pair of doubles for Double-A Chattanooga. Gordon finished the afternoon 2-for-5, scored a trio of runs and is hitting .315 through 64 games in his first taste of Double-A ball.
• No. 68 overall Justus Sheffield (Yankees' No. 6) spun his first career shutout (7 innings) as he led Double-A Trenton to a 6-0 win over Erie in Game 1 of a doubleheader. Sheffield, who has won back-to-back decisions and has a 2.99 ERA through 13 starts, gave up just three hits and walked one. Sheffield threw 62 of his 97 pitches for strikes in the game, but notched just three strikeouts, his lowest total this season.
"I hold myself to a high standard every time out there and every time I'm out there, I'm shooting for the limits," Sheffield told MiLB.com. "I knew we had seven [innings] today and I wanted to get seven in. … I feel like if you set yourself at a high standard, you'll be able to be efficient, keep the pitch count low and pitch deep into games. That's one of my goals this year."
• No. 84 overall Jeimer Candelario (Cubs' No. 4) posted his second multihit game in the past three days for Triple-A Iowa. Candelario did it all for the I-Cubs as he reached base five times and scored three runs. The 23-year-old finished 2-for-4 with a double, homer and also drew two walks.
• Angels' No. 2 prospect Matt Thaiss hit his seventh homer of the season and second over the past three days for Class A Advanced Inland Empire. Thaiss, who is hitting .263 this season hit a three-run homer in the eighth inning of the 66ers' 8-6 loss and finished the game 3-for-5 with three RBIs.
• Blue Jays' No. 29 prospect Jonathan Davis set a career high with four hits for Double-A New Hampshire. Davis, the Fisher Cats' leadoff man, went 4-for-5 with a double and an RBI, but his teammates only drove him in once and New Hampshire fell, 13-7, to Bowie.
• D-backs' No. 30 prospect Christian Walker leads the Pacific Coast League with 68 RBIs after driving in a trio of runs for Triple-A Reno. Walker, who has played in 67 games, drove in two runs with a base hit in the fifth and added a sacrifice fly in the sixth. The 26-year-old set his career high in 2014, when he drove in 96 runs across two levels.
• Giants' No. 8 prospect Joan Gregorio threw five scoreless innings for Triple-A Sacramento. Gregorio struck out eight, a season high, in the outing, while surrendering five hits and a walk. The outing was a nice rebound for the 25-year-old, who gave up four runs in 5 1/3 in his last start, but did strike out seven and has fanned 15 over his last 10 1/3 innings.
• Orioles No. 7 prospect Austin Hays went 5-for-5 with two homers, two doubles and six RBIs for Class A Advanced Frederick. Hays extended his hitting streak to eight games with the massive offensive showing and is hitting .328 with 16 homers and 41 RBIs through 64 games in his full-season debut.
• Padres No. 6 prospect Fernando Tatis Jr. hit his ninth homer of the season as part of a 2-for-4 effort with Class A Fort Wayne. The 18-year-old is hitting .260 through 54 games of his full-season debut after hitting .273 over 55 games in rookie- and short-season leagues last season.
• Reds' No. 5 prospect Luis Castillo flirted with a no-hitter, but ultimately suffered a tough-luck loss for Double-A Pensacola. Castillo threw six hitless innings, but gave up a single to open the seventh and four batters later the Blue Wahoos lost on a walk-off single. Castillo gave up 1 earned run on two hits in 6 1/3 innings.
"He was on top of his game, he pitched in and out," Pensacola pitching coach Danny Darwin told MiLB.com. "He pitched down in the zone, he pitched up in the zone. He had a big league changeup and threw some very good sliders."
• Reds' No. 6 prospect Tyler Stephenson doubled and hit his fourth homer of the season for Class A Dayton. The Dragos lost to Fort Wayne, but Stephenson had a solid day, going 2-for-4 with three RBIs.
• Red Sox's No. 9 prospect Nick Longhi put together his third three-hit game of the season in Double-A Portland's loss to Akron. Longhi went 3-for-4 in the game and also hit his fifth homer of the season, a two-run blast in the first inning.
• Twins' No. 7 prospect Travis Blakenhorn hit his eighth homer of the year for Class A Cedar Rapids. Blakenhorn set a season high with four hits and he went 4-for-5 with three RBIs.