Borkowski was brought up to replace Oscar Villarreal, who was designated for assignment.
"My first day down there I threw a bullpen [session], and right away [pitching coach] Burt [Hooten] noticed I was too spread out in my feet," Borkowski said. "I wasn't getting my weight back on my back leg and was just kind of rushing forward. My arm was dragging."
Borkowski, who was designated for assignment after starting the season 0-2 with a 6.86 ERA in 18 relief appearances, was sent to the Express to fix whatever problem was holding him back.
He said Hooten recognized immediately everything that was wrong and pushed him in the right direction.
"We made a couple other adjustments and really from Day 1, I started to feel like my old self," Borkowski said. "Burt's extremely knowledgeable. He's been around this game a long time. He knows the ins and outs of pitching like he's reading a book."
After an 0-2 start to the season with Houston, Borkowski went 1-1 with Round Rock with a 2.29 ERA in 12 appearances, even garnering a five-inning start.
He allowed five earned runs over 19 2/3 innings with five walks and 12 strikeouts.
Astros manager Cecil Cooper said he will use Borkowski for relief, despite his recent starting stint.
"We just need someone to be able to give us multiple innings," Cooper said. "That's what we'd hoped Villarreal would do for us. [Borkowski has] been stretched out, so he can do the kid of work we envisioned for Oscar."
Borkowski said he got the assignment Wednesday afternoon, packed as much as he could and hurried to Houston to be ready for tonight's game.
"It feels great that they can rely on me again and know that the first couple months here was more of a fluke than me not being able to pitch," Borkowski said. "I proved that. I went down there and worked hard -- I didn't throw myself a pity party and sulk about it. I got my stuff right, and it worked out for me."
Krysten Oliphant is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.