Bolsinger tossed 5 2/3 hitless innings before Jake Smolinski reached on an infield single Tuesday as the Double-A Mobile BayBears beat the Jacksonville Suns, 3-1, in the second game of a doubleheader.
The 24-year-old right-hander also surrendered a run-scoring triple to Curt Smith but retired Kyle Jensen to end the sixth. Bolsinger exited for a pinch-hitter in the seventh and was charged with a run on two hits while striking out five.
"Basically, I was just locating my cut fastball in," he said. "That basically is my fastball. I was locating well, going inside with it, going outside with it and they'd roll over on it.
As for Smolinski's slow roller to second base, Bolsinger said, "It was one of those little choppers that just gets over the pitcher and it's soft enough that he could beat it out. A hit's a hit."
Bolsinger, who walked three, was promoted from Class A Advanced Visalia on May 17. The 2010 15th-round Draft pick is 2-1 with a 3.57 ERA in three Southern League starts and has fanned 16 batters in 17 2/3 innings. In his last outing, however, he surrendered five runs on six hits over five innings in a loss to Tennessee.
"My last start, things didn't go the way I wanted to," Bolsinger said. "My fastball location was off, and today I got back into what I want to do, throwing the cutter in to hitters, which allows me to do more stuff with my curve and slider. Hopefully, I can take that and get myself right back into a rhythm."
Bolsinger joined the BayBears after the Diamondbacks bumped top prospect Trevor Bauer up to Triple-A Reno. While the University of Arkansas product doesn't give it much thought now, he had a different reaction before his Double-A debut.
"The first game that I came up, I remember going on the Jackson web page and they were like, 'Bauer vs [Mariners top prospect Danny] Hultzen,'" Bolsinger said. "I'm like, 'Man, people were going to come to the game and go, 'Where's Bauer? Who's this Bolsinger guy?'
"I just treat it as me getting called up and try to continue what I did. And that's it."
That "Bolsinger guy" started the season with seven impressive starts in the California League, going 3-2 with a 2.37 ERA and 49 strikeouts. He's given up only two homers over 55 2/3 innings across the two levels.
Evan Marshall followed Bolsinger to the mound Tuesday and tossed a perfect seventh to notch his 11th save.
David Nick went 3-for-4 with a double and an RBI, while Marc Krauss, the D-backs' No. 20 prospect, doubled home a pair of runs for the BayBears.