Then a starter for the Rangers, the right-hander was off to a subpar start against left-handed hitters in his first season in the American League. That year, lefties batted .305 against the Nicaraguan native.
So he attempted a new gimmick. Instead of firing a traditional pitch versus lefties, he tossed a slower one with the element of surprise. While Padilla doesn't remember the guinea pig for the first experiment, he could vividly recall the shock of the sequence.
"It just left my hand –– I threw a slow curving pitch for a strike, and the batter just froze," Padilla said, laughing. "Then I thought, 'Hey maybe this pitch could actually help me.' That's when I started to work on it more."
And then, the eephus pitch was born. Six years later, Padilla is still unleashing the unconventional pitch, but now it's with the Red Sox. Padilla's eephus made its spring training debut March 5, when he froze Twins catcher Joe Mauer on a 53 mph toss.
During his days with the Dodgers, Padilla's pitch was dubbed the "soap bubble" by legendary broadcaster Vin Scully. Upon release from his hand, the baseball floats in the air –– in between 50 and 55 mph –– and breaks ever so slightly at the plate.
"I like to use it every once in awhile to catch the batter off guard," Padilla said. "Sometimes, I have the batter guessing or sometimes they're wondering if I'll throw it on the first pitch or the second pitch."
The slow movement and deceptive timing of the eephus usually stymies opposing batters. Just ask Red Sox designated hitter David Ortiz.
"He threw it to me a few times and I never hit it," Ortiz said. "I'm just glad he's on my side."
But Padilla's in the major-league minority. The only active hurlers to incorporate the pitch in their stash are Miami's Mark Buehrle and Houston's Livan Hernandez. Of the trio, Padilla likely leans on the eephus the most often.
There are gambles that come along with the eephus. By tossing such a slow curveball, Padilla is essentially exposing himself to hitters –– who are prepared for the pitch –– to unload the long ball.
Even with that possibility, the 34-year-old isn't deterred.
"The risks are just like any other pitch," Padilla said. "If you throw a fastball 100 [mph], if the batter is ready for it, they'll knock it out the park. It isn't any different for the eephus. If they're prepared for it, they can knock it out. The risks are the same, but with that pitch, I have confidence in it the moment I throw it."
That assurance allows Padilla to switch velocities in the blink of an eye. Against the Rays on March 18, the right-hander fanned first baseman Carlos Pena with a quick pitch combination that spanned 40 mph.
"That at-bat to Pena with the 53, 73, 93 [mph], three pitches in a row, I don't think you'll see that many times," Red Sox skipper Bobby Valentine said. "He's an accurate thrower. His stuff seems to be pretty good."
During his last extended stint in the majors, left-handed hitters discovered that lesson firsthand, hitting just .167 against Padilla in 2010. It was the same year that Padilla made his last Opening Day start.
For now, the Nicaraguan native is nursing a hamstring injury, one he suffered Monday in the weight room. Once he's healthy, the Red Sox should expect to see the vaunted eephus back in action.
"I don't plan on using it a lot," Padilla said. "But it's just one more pitch in my arsenal."