With Scott Rolen out up to six more weeks after having left shoulder surgery on Wednesday, the Reds are currently using Miguel Cairo and Todd Frazier at third base. Shortstop Paul Janish can also play there. Third base prospect Juan Francisco is currently on Triple-A Louisville's disabled list because he had right knee surgery on July 8.
While at the University of Miami, Alonso was taken as a first baseman by the Reds with the seventh overall pick in the 2008 First-Year Player Draft. Since he's blocked there by Joey Votto, he began playing left field last season.
"When I got to college at Miami, Ryan Braun was at third base. That's why I moved to first base," Alonso said. "I started playing third my sophomore year and Danny Valencia came. He's now with Minnesota. Those were two pretty good third basemen."
Since his big league promotion on July 26 after the Reds traded left fielder Jonny Gomes to Washington to clear a roster spot for him, Alonso hasn't played much. His only start was in left field on Monday vs. the Astros, and he was not in the lineup on Tuesday or Wednesday.
Alonso, 24, entered Wednesday hitting 3-for-8 (.375), after he batted .296 with 12 home runs and 56 RBIs in 91 games for Louisville.
"It's part of the process, I guess. My time will come," Alonso said. "I will pretty much stay with it, work every day and prepare myself for whatever that role may be. If I start, I start."
Alonso felt like his one start was successful, as he made one catch. But he also looked tentative on another fly ball that dropped in front of him. That, he said, was because he feared the ball getting by him had he made a diving attempt.
"I thought I played pretty well," Alonso said. "There were a couple of balls that kind of dunked in there. I caught a fly ball, hit my cutoffs and had good at-bats. It's just one start. It's not like it's the 100th start in the big leagues. I take it for what it is, and try to grasp as much positive as I can and move forward with it to the next start."
Alonso made a pinch-hitting appearance in the ninth inning of Wednesday's game and delivered an RBI single in the Reds' eventual 5-4 loss to the Astros.