Once given his release, Paul said he was in contact with quite a few teams. He liked his chances with the Reds most.
"First of all they were winning," Paul said. "I knew they didn't have that many lefties on the bench. I've had that role before with Pittsburgh and the Dodgers. I wanted to show them I could do it here."
In six games with Louisville, the 27-year-old Paul was batting .480 (12-for-25), and he was batting batting .332 with nine homers and 48 RBIs in 66 Triple-A games overall. He broke into the Majors in 2009 with the Dodgers and spent most of last season with the Pirates, batting .255 with two homers, 20 RBIs and 16 steals.
"I liked him when he was with the Pirates," Reds manager Dusty Baker said. "He was one of the best pinch-hitters around, especially against right-handers. He can play all three outfield positions and gives us that much needed left-handed bat. He has speed, which we also need."
Paul batted .279 vs. right-handers last season, and .262 for his career. Against lefties, he hit only .071 in 2011 and .148 lifetime. He batted only .093 as a pinch-hitter last year.
With Joey Votto on the disabled list after having knee surgery, Jay Bruce was the lone left-handed bat on Cincinnati's roster. With Willie Harris and Mike Costanzo getting looks in the first half and both struggling, the Reds have had little luck with lefties on their bench this season.
"I was praying that hopefully they call my name," Paul said. "Fortunately that happened. Unfortunately, it was Joey that got injured. It feels good to be here. Hopefully he recovers real soon and he's back continuing what he does best."
Paul made his Reds debut pinch-hitting in the seventh inning of Wednesday's 7-1 loss to the D-backs. On the first pitch, he flied out to center field.
To make room, pitcher Todd Redmond was optioned back to Louisville. Redmond was called up on Tuesday and did not appear in the game vs. Arizona.