"That's the only thing that bugs me," said Tropeano, who's still fourth in the league in WHIP.
The Astros' No. 17 prospect struck out eight over seven scoreless innings Saturday as the Class A Lexington Legends posted a 5-1 road win over the Asheville Tourists.
Tropeano (2-2) allowed only a single to Delta Cleary in the third and a double to Harold Riggins in the seventh. He retired 10 straight Tourists in between and estimated that he threw 84 pitches.
"I felt the groove going on, trying to get that first pitch for strikes," said Tropeano, who also issued -- and was annoyed by -- two more free passes.
The 2011 fifth-round Draft pick had allowed seven runs on 10 hits over 7 2/3 innings in his previous two starts, both losses. He said jumping ahead in the count was key to his improvement.
"Last outing, I was battling throughout the game, falling behind hitters," the 21-year-old right-hander said of Sunday's start against Savannah. "This was much better."
Tropeano's 1.87 ERA through six outings ranks fifth among active South Atlantic League starters. With strikeouts leader Matt Barnes just promoted to the Carolina League, Tropeano also leads the circuit in that category (41 in 33 2/3 innings).
"I'm happy, but you can allways get better each time out," he said.
The Legends employed a balanced offensive attack Saturday. Each member of the starting lineup recorded a hit and four plated runs.
Tourists starter Chris Jensen (2-1) gave up all five runs on eight hits, exiting after five frames.
Jordan Ribera slugged a solo homer, his first of the season, off Legends reliever Murilo Gouvea in the ninth to avoid a shutout.