ST. PETERSBURG — There were certain things the Rays expected to see when they finally promoted top outfield prospect Desmond Jennings to the big leagues in late July.
Speed. Smothering defense. Gap-to-gap hitting. Instincts on the bases. An occasional bunt hit. Overall athleticism. And, perhaps most important, quality at-bats as a product of his command of the strike zone.
What they didn't expect to see: balls soaring out of stadiums off his bat.
Jennings' five home runs in 24 games are impressive enough, second among the Rays to only Evan Longoria's six since the July 23 callup, and more than all but nine other American Leaguers.
But it's how far they are going, and how quickly they are getting out, that has been most stunning.
"I didn't know he could do that," manager Joe Maddon said.
There was a laser to left in Oakland in his sixth game, estimated at 406 feet. An opposite-field shot at the Trop of 375 feet. And Tuesday's blast over the Green Monster and out of Fenway Park, at 415 feet.
"I knew he could hit a home run, but the home runs he's hit have been really far," Maddon said. "So there's more raw power than I had known about."
Jennings is quiet and humble by nature, and he didn't offer much in the way of an explanation. He has been pretty much healthy all season, and at 24, after nearly 1,000 plate appearances at Triple A, is more mature as a hitter.
"I don't know what to say," he said. "I guess I'm getting stronger. I'm stronger than I was last year. But I don't know."
Hitting coach Derek Shelton said the key has been the tremendous bat speed Jennings generates with his hands and wrists, specifically in the final 6 inches before contact.
"He's really getting through the zone," Shelton said. "He's shown a ton of bat speed, he's showing the ability to stay behind the ball, and he's showing strength off the bat. The way he's swinging the bat, the ball's coming off hot."
Jennings' high for any of his first five pro seasons is 11 homers in 2009, eight in 100 games at Double-A Montgomery and three in 32 at Triple-A Durham.
But he had 12 in 89 games for the Bulls this year, and with five so far for the Rays, he has put on a power show.
The 30-plus he projects for a full big-league season is probably a little heavy, but the Rays are certainly intrigued by the possibilities, especially with the discipline he has shown at the plate, swinging at the right pitches and, just as important, not swinging at the wrong ones.
"So you've got raw power and then it's the frequency of the power," Maddon said. "It comes down to contact, making adjustments to the pitches, etc. So far I'm seeing the adjustments being made, and he's got a history of having an organized strike zone, which I think benefits him too.
"He may have 20 in his future."
Jennings laughs off the question, saying he's still getting used to the whole power trip. "I haven't hit that many homers," he said. "When I hit them, I don't know."
Watching in awe from the dugout, the Rays coaches know. And they like what they've seen so far.
"He's a game-changer," Shelton said. "He can change the game with his glove, he can change the game on the bases and he can change the game with his bat. When you get guys like that, you've got someone special."