Happ, whom the Cubs selected with the ninth overall pick in the 2015 Draft, has hit .322/.426/.522 in 74 games to begin his first full professional campaign.
As for McKinney, the Cubs' No. 6 prospect (No. 79 overall) went 2-for-3 with a triple and four RBIs for the Smokies, while also reaching base via a walk. After posting a .525 and .776 OPS during April and May, respectively, the 21-year-old outfielder has continued to make offensive strides in June with a .782 OPS through 22 games.
The rest of the best performances from top prospects Monday
• No. 27 overall prospect Aaron Judge hit another home run in Triple-A Scranton/Wilkes-Barre's shutout over Syracuse. The Yankees' No. 2 prospect has now gone deep seven times in his past nine games for the RailRiders, giving him 16 home runs in 73 games for the season.
• No. 54 overall prospect Josh Hader (Brewers' No. 4) turned in his first scoreless start since being promoted from Double-A as he fired five strong innings for Triple-A Colorado Springs in its 3-2 win over Round Rock in 14 innings. The 22-year-old southpaw allowed three hits and two walks while fanning eight, throwing 61 of his 102 pitches for strikes. Between both levels, he's posted a 1.87 ERA with 99 strikeouts in 77 innings.
• No. 61 overall prospect Amir Garrett struck out five hitters over seven scoreless innings, allowing four hits and two walks, in relief of Homer Bailey for Triple-A Louisville, which fell to Buffalo, 3-1. It was the Reds' No. 4 prospect's second outing since moving up from Double-A Pensacola, where he logged a 1.75 ERA and held opposing hitters to a .184 average while working 77 innings.
• No. 66 overall prospect Daz Cameron (Astros' No. 5) recorded his first four-hit game and fell a double short of hitting for the cycle in Class A Short Season Tri-City's win over Lowell. The 19-year-old outfielder finished the game with three RBIs, two of which came on his first pro home run in the fourth inning. Cameron is hitting .267 through 10 games for Tri-City since being demoted from Class A Quad Cities, where he slashed just .143/.221/.221 with 33 strikeouts in 21 games.
• No. 83 overall prospect Hunter Renfroe hit a grand slam -- his 18th homer of the season -- as part of a three-hit performance in Triple-A El Paso's rout of Reno. The Padres' No. 3 prospect has collected multiple hits in three of his last five games for the Chihuahuas.
• Cubs No. 20 prospect Dan Vogelbach collected three extra-base hits as part of a five-hit day for Triple-A Iowa in a twin bill split against Oklahoma City. The 23-year-old first baseman hit his 15th home run -- his third straight game with a homer -- and a pair of doubles while driving in four runs in the opner before going 2-for-3 with two singles in the nightcap. He's collected multiple hits in four straight games for the I-Cubs to lift his season average to .313 from .293.
• Giants No. 22 prospect Ty Blach hurled the third shutout of his career in Triple-A Sacramento's win over Las Vegas. The southpaw scattered six hits, struck out six and induced 10 ground-ball outs in the performance, which he needed just 94 pitches (72 strikes) to complete.
• Mets No. 7 prospect Wuilmer Becerra paced Class A Advanced St. Lucie's offense in a 17-0 blowout of Jupiter by going 3-for-5 with five RBIs. One of those hits was a two-run homer, his first of the season, and he also tallied his 12th double. With Monday's multi-hit performance, Becerra, 21, lifted his season average to .316 through 50 games.
• Making his third start of the season for Class A Short Season Williamsport, Phillies No. 16 prospect Adonis Medina took a no-hit bid into the ninth inning before allowing a one-out single on his 99th pitch. He struck out four, walked one and hit two batters over 8 1/3 innings. The 19-year-old right-hander has yet to allow an earned run this season, and he's allowed six hits over 21 innings in that span.
• Phillies No. 22 prospect Dylan Cozens blasted his 20th home run -- a third-inning grand slam -- to tie Double-A Reading teammate Rhys Hoskins and Travis Demeritte for the Minor League lead as the Fightin Phils walked off Erie in the bottom of the ninth, 8-7. The 22-year-old outfielder is pacing all Eastern League hitters with a .913 OPS, 62 runs scored and 160 total bases, and he also ranks third with 60 RBIs. He's hitting .273/.360/.554 through 75 games.
• Fresh off of an appearance on MLBPipeline.com's latest Prospect Team of the Week, White Sox No. 9 prospect Courtney Hawkins stayed red-hot on Monday as he went 3-for-3 with two doubles and four RBIs in Double-A Birmingham's loss to Mobile. The 22-year-old has been on a tear of late, with a .571 average (12-for-21), two homers, four doubles and 13 RBIs in his last five contests.
• Yankees No. 7 prospect Domingo Acevedo hurled his first career shutout, tossing seven innings of five-hit ball to lead Class A Advanced Tampa past Brevard County in the second game of a doubleheader. The 6-foot-7 right-hander scattered five hits and fanned six and needed just 73 pitches (55 strikes) to complete the shutout. He's allowed five earned runs in 16 2/3 innings (three starts) since moving up to the Florida State League.