Of course, the transaction will look a lot better if Purpura is able to sign Jennings, a free agent after this season, to a long-term contract. But for now, Purpura's concerns rest solely with the on-the-field issues. He needed a No. 2 starter, and in Jennings, he found his man.
It cost him two serviceable Major Leaguers in Willy Taveras and Jason Hirsh, and also Taylor Buchholz, who has yet to establish himself at the highest level. But from Purpura's view, he obtained a top-of-the-rotation pitcher who could be the ace of many staffs -- just not Houston's, because of Roy Oswalt.
Jennings, a 6-foot-2, 235-pound right-hander, brings a solid resume with him from Colorado, the only team he knew after being drafted as the Rockies' No. 1 pick in 1999.
Obviously, he knows how to pitch in arguably the toughest surroundings for a pitcher in the big leagues. In mile-high conditions known as the worst pitchers' park in the history of baseball, Jennings logged more wins (31) and starts (73) than any pitcher in Coors Field history.
Those credentials were more than enough to make Jennings a major offseason target.
"You look at a guy with a below-four ERA, in this day and age, and he's the winningest pitcher in the history of that franchise and the winningest pitcher in that ballpark," Purpura said. "No. 1, he's been successful at Coors Field. Plus, you look at his competitiveness, the way he goes about his business. I've always liked the way he competes, how he goes after hitters."
The Astros can rest assured that the Jennings they watched and scouted over the years won't change now that he's in new surroundings. Learning from other pitchers' shortcomings while remaining confident in his own abilities, Jennings did not let thin air alter his approach. It's likely a short left-field porch won't faze him, either.
"Most of the time, the Crawford Boxes, if it's hit to left, usually, it's going to be a home run at any park," Jennings said. "Occasionally, you'll get a cheapie. You take that mentality and you don't let the ballpark affect how you throw -- like, I can't throw this pitch because I'm pitching at home or pitching on the road or whatever. As a pitcher, you have to go out with the same game plan, the same mentality as you do any park, any day."
Jennings keeps it simple, something that he admits took him a couple of years to learn.
"The key is just to change speeds on your fastball, move the ball back and forth and use your changeup, which has been a big pitch for me the past couple of years," he said. "Hopefully, I can take those same thoughts and game plans into Minute Maid and have success there. I know it's not a pitchers' park, but neither is Coors Field, and I've had to do that for five years."
Of course, being a sinker-ball pitcher doesn't hurt, either. Manager Phil Garner noticed an improvement in that pitch last year, and given Jennings' five years of service time, Garner senses Jennings may be in for a fruitful 2007.
"I consider five years, 1,000 innings right about the time when most guys start to come into their own," Garner said. "Five years, 200 innings a year. If you're going to be a good pitcher, you're going to figure it out. I think he's shown that."
"For whatever reason, he just felt more comfortable using that pitch," Purpura said of the sinker. "I think it's going to be a good pitch in that ballpark. We do traditionally look at fly ball-ground ball ratios when we're looking at pitchers to obtain, and he's one that sort of stuck out like a sore thumb."
Durability is a factor, too. Jennings has logged just over 900 innings in his five full seasons in the Major Leagues, including his 2005 campaign, which was cut short because of a fractured finger he suffered while sliding into second base. He rebounded in 2006 to log 212 innings, a career high.
Although Jennings hasn't posted a winning record since he was 16-8 in 2002, Purpura is confident that Jennings will flourish on a team that has high expectations to win, along with a history of postseason participation. That's something the Rockies, in their 15-year history, have not been able to provide with any consistency.
"Even when we made the trade, I called Jason and one of the first things I said to him was, 'We're all about winning. We eat, sleep and drink it. That's what we're here to do,'" Purpura said. "He said, 'That's refreshing to hear.'"
Added Jennings: "All you have to do is look at the past 10 years. [The Astros have] won and the Rockies haven't. It's not bashing, it's just the truth. That's something I'm not necessarily used to. We had spurts of good games when I was with the Rockies, but it's nothing like [the Astros] have done. Hopefully, I can come in and contribute to that."
Alyson Footer is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.