The No. 81 overall prospect struck out 10, a career-high, in six scoreless innings for Class A Advanced Salem. Kopech threw 53 of his 78 pitches for strikes, walked one and surrendered one hit.
While that line is impressive, it's nothing new as the 20-year-old has been twirling gems ever since he returned to the mound. Kopech, the Red Sox's No. 5 prospect, has held opponents scoreless in four of his seven starts this season and has posted a 1.10 ERA in 32 2/3 innings.
The rest of the best performances from top prospects Tuesday:
• No. 21 overall prospect Lewis Brinson introduced himself to his new organization with a 4-for-4 day at the plate. The Brewers No. 2 prospect showed off his offensive prowess for Triple-A Colorado Springs a day after he was traded from the Rangers as part of the Jonathan Lucroy deal.
• Cubs No. 2 prospect Eloy Jimenez (No. 31 overall) extended his hitting streak to nine games for Class A South Bend. The 19-year-old went 3-for-4, marking his 10th three-hit game of the season. Jimenez has two or more hits in seven of the nine games during his streak and is hitting .347 through 95 games this season.
• No. 32 overall prospect Mickey Moniak (Phillies' No. 2) extended his hitting streak to six games and bumped his average up to .326 with a 2-for-5 day for the GCL Phillies. The 18-year-old drove in his 22nd run of the year and added a double and triple.
• Indians No. 1 prospect Bradley Zimmer (No. 33 overall) hit his first Triple-A homer and went 3-for-4 for Triple-A Columbus. Zimmer has hits in six of eight games since his promotion, but this was also his first three-hit night at the higher level.
• Another day, another hit for Francisco Mejia. Such is life for Indians No. 4 prospect.The No. 100 overall prospect extended his hitting streak to 44 games, the eighth longest in Minor League history, with a single in the first inning. The catcher finished 2-for-3 with an RBI for Class A Advanced Lynchburg.
• It was déjà vu for Max Pentecost (Blue Jays' No. 14) as he went 2-for-4 with a double, triple and a pair of RBIs for Class A Lansing. This came a day after Pentecost went 2-for-4 with a double, triple and two RBIs.
• Blue Jays' No. 21 prospect Yennsy Diaz set a season-high with eight strikeouts in six scoreless frames for Rookie-level Bluefield. The 19-year-old walked one and gave up two hits in his first scoreless outing of the season.
• Kyle Muller (Braves' No. 12) extended his scoreless streak to 11 innings in a start for the GCL Braves. Muller, the Braves' 2nd-round selection, gave up two hits and struck out five in three innings. The lefty has a 1.02 ERA through 17 2/3 innings and hasn't given up an earned run in three consecutive starts.
• Luiz Gohara (Mariners' No. 5) twirled another gem for Class A Clinton. The lefty gave up one run on two hits in seven innings and has given up a total of two earned runs over 13 frames in his past two starts. Gohara has carved up lineups all season as he is 5-1 with a 1.94 ERA through nine starts across two levels.
• Andrew Moore (Mariners' No. 10) needed just 97 pitches to notch his first career shutout. The 22-year-old struck out four and gave up just five hits in Double-A Jackson's 1-0 win over Montgomery. Moore is now 7-1 with a 2.78 ERA since joining the Generals.
• Nationals' No. 27 prospect Joan Baez hurled one of his best starts of the season for Class A Hagerstown as he gave up one run on five hits in six innings. Baez struck out eight and threw 59 of his 91 pitches for strikes.
• Phillies' No. 8 prospect Roman Quinn's rehab assignment is going quite well. The outfielder went 3-for-4 with a double and a stolen base with the GCL Phillies and has a hit in each of the six games he's played with the squad. Over his past four games, Quinn is 9-for-16.
• Ben Lively (Phillies' No. 24) led the way in Triple-A Lehigh Valley's 2-1 win over Scranton-Wilkes/Barre. The 24-year-old right-hander gave up one run (unearned) on three hits in eight innings. Lively walked one and fanned eight.