SCOTTSDALE, Ariz. -- The Cardinals sent Zack Thompson to Triple-A for 2021, his first full professional season. That aggressive assignment didn't go as planned.

The left-hander selected 19th overall in 2019 out of Kentucky went 2-10 with a 7.06 ERA at Memphis. Triple-A East hitters batted .302/.400/.516 against him, and his K/BB ratio was a mere 82/57 in 93 innings. After finding some success in July and August, he gave up 19 runs in 14 innings in four September starts.

Thompson has looked like a totally different pitcher in the Arizona Fall League, however. The No. 8 Cardinals prospect recorded his fourth consecutive scoreless outing for the Glendale Desert Dogs on Monday, earning his first victory in a 7-6 defeat of the Scottsdale Scorpions.

Thompson worked two hitless innings, sitting at 92-94 mph with his fastball and snapping off some quality curveballs while striking out two and issuing two walks. He has yielded two hits in eight AFL frames, fanning 13 while walking seven. No pitcher on the developmental circuit has worked as many innings without surrendering a run.

"I saw this as a chance, rather than as a continuation of the season. It's like a new season, a chance to start over and start fresh, work on a couple things," Thompson said. "I messed with a few things toward the end of the Triple-A season, and I think it's really worked out here."

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Thompson came to Arizona determined to rely more heavily on his curveball, his best pitch. He has worked in middle relief, primarily focusing on his fastball and curve while gaining more confidence in his changeup. He also has turned his slider back into more of a cutter.

Coming off a pandemic layoff during which most of his development came at home -- he got some time at the Cardinals' alternate site last summer, but they didn't run an instructional league program in the fall -- as a result, Thompson's stuff was down at the beginning of 2021. Once he started to get hit, he looked tentative at times. In the Fall League, his fastball and curveball have resembled the pitches that made him a first-round pick and he's been aggressive, albeit with a few more walks than he'd like.

"I was definitely excited to go to Triple-A," Thompson said. "Making it to the last round of cuts in camp and heading to the alternate site kind of mentally prepped me to be ready for Triple-A. Going into it, I think I went in a little cocky -- 'I know it all and I'm ready to go to the Triple-A level' -- and I wasn't. I had to learn some things...

"I didn't have the velo to start the season and the curveball wasn't quite as good. That's really what forced me to learn a changeup. Triple-A this year [wasn't good,] but it forced me to learn a changeup, so I got something great out of it."

Cardinals first baseman Juan Yepez (No. 27) powered the attack for Glendale (7-4) with three hits and three RBIs, taking over the AFL lead in the latter category with 14 in nine games. He also tops the league with eight extra-base hits, adding to that total with a first-inning double and a ninth-inning homer. The blast traveled 428 feet with an exit velocity of 107 mph against Red Sox left-hander Brendan Cellucci.

Scottsdale dropped to a league-worst 3-8 despite more heroics from Red Sox second baseman Jeter Downs, who homered in his fifth consecutive game. His eighth-inning grand slam was a 385-foot opposite-field shot at 101 mph at the expense of Dodgers right-hander Kyle Hurt. Boston's fifth-ranked prospect leads the Fall League in homers (five in six games), slugging (1.048) and OPS (1.565).