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"It ain't over 'til ..." OK, well, maybe it's over.

I'm a big fan of Yogi Berra's, but he has obviously never played in a keeper league.

It's noble to do everything you can to win a championship, but as a keeper-league veteran, let me assure you, you cannot possibly win every season. (If you are somehow doing this, find yourself a more competitive league.) Player values change too rapidly, and decisions that you make impact your team over a much longer period of time.

That's why it's almost as integral a trait of a keeper-league owner to know when you're beat, as it might be possible to be able to make the moves to get you to the top in the future. This isn't a redraft league, where once you're out of the running, you can turn your attention to football, basketball or hockey, or go hibernate with the "other" Yogi. Once your current season is for all intents and purposes done, your work for 2009 has already started.

So with most keeper-league trade deadlines right around the corner -- mine are generally around Sept. 1 -- I challenge you: Check your team's standings, and I mean in detail. Do you have a shot at a title? Or is it a hopeless cause? (I suggest you really do the math, not make a from-the-gut guess.)

If it's time to complete the Yogi quote and declare "it's over," then this column is for you.

August presents most owners their final chance to turn over roster spots for 2009; that gives you only 23 days to unload any worthwhile non-keeper commodity, while scoring bargains, prospects and next-year sleepers in exchange.

But whom should you target? You'll see my top 100 keeper list on the right. If you've got the rental parts to deal to a contender in exchange for one of those top-flight studs, by all means, take your best shot. I'm of the mind that you aim for the best player you can get in any deal. On the other hand, I think Shawn Peters made an excellent point that we're running up against deadlines at this stage of the season, so don't mess around.

That's why when I'm thinking keepers, I'm often looking at guys with high ceilings whom you might be able to sneak through on the cheap. Names like the ones below. No, you won't find a Francisco Liriano, David Price or Matt Wieters on the list. Those are obvious names, youngsters everyone knows will be great, ones you'll have to pay a steep bounty to acquire. Instead, the following are guys whose recent performance or health problems might have cast some doubt in people's minds about their future value, but have the potential to break through once again next year.

Chris Carpenter, SP, Cardinals: He's a risk I am willing to take, and it might be because I have a lot of faith in manager Tony La Russa and pitching coach Dave Duncan. Feel free to add "magicians" to their titles. Seriously, who doesn't turn into gold under their watch? Carpenter, simply put, brings substantially greater talent to the table than any of the Cardinals' other pitching finds of the past couple seasons, and so far, he's looking pretty decent for a guy fresh off Tommy John surgery. The list of pitchers who have mounted massive comeback seasons in their second seasons after recovering from that operation is somewhat lengthy, but few of the names have the track record of Carpenter. He might be risk/reward for 2009, but that'll depress his trade price tag today, and he's in a situation that greatly increases his chances of reward.

Manuel Corpas, RP, Rockies: Not that I think it's smart to build a keeper list around closers, but if you need a dirt-cheap trade target almost assured of being in that role next Opening Day, Corpas is your man. Brian Fuentes is a free agent, and with the Rockies having already signed Corpas to a four-year, $8.025 million contract (that could increase in value to six years, $22.775 million), the latter will get a long look in the spring. By the way, Corpas hasn't pitched poorly at all of late, with a 1.42 ERA, 0.89 WHIP and .225 batting average allowed in his past 19 appearances.

Stephen Drew, SS, Diamondbacks: This one has nothing to do with a belief Drew is going to develop into a fantasy mega-stud. It has everything to do with the future of the position. Within two years, the cream of the shortstop crop might be Hanley Ramirez -- if he's not shifted due to his so-so defense -- Jose Reyes, Troy Tulowitzki and ... Drew, a very good, even if not exceptional, talent. All of his numbers except batting average are right in line with his rookie year in 2006, and that 2006 number (.316) was driven by an unreal .394 batting average on balls in play. And if you think back to 2006, most felt Drew was a player who could bat in the .290 range with 25-, maybe 30-homer power at his peak. If he's a .278 hitter on pace for 19 homers this year, I don't see why at age 26 in 2009 he couldn't bat, say, .285 with 25 long balls. I don't know about you, but I'd call that a top-five fantasy shortstop, but he'll cost you much, much less than that today.

Yovani Gallardo, SP, Brewers: This might seem an obvious pick, but then the guy has made only three starts all season, and his disabled-list status could have some doubting his ability to bounce back in 2009. Count me among the faithful. Gallardo's surgery was on his knee, not his pitching arm, and it was as a result of a fluke in-game incident, not normal wear and tear. He hasn't even ruled himself out entirely for 2008, despite conventional wisdom suggesting ACL surgery is a season-ender. That might seem foolish, but I read it differently; I see it as drive and determination in the player to rehabilitate himself to a high level, knowing his team is in a pennant chase (though I admit, I'd prefer he didn't actually appear in a game). Either way, Gallardo should be fine in the spring, and so far in his career, when he has been healthy, he has been excellent.

Alex Gordon, 3B, Royals: When a player ranks as a disappointment in back-to-back seasons to begin his career, a stigma seems to build around him. Fantasy owners -- many of them terribly impatient -- tend to think, "Is this it?" In Gordon's case, the problem is the expectations were wholly unrealistic entering 2007, though over the long haul they might yet be right on target. Gordon's walk rate has improved, up from one per 14.6 plate appearances in 2007 to one per 8.6 this year, both his line-drive and fly-ball rates are up slightly from last season and his isolated power in his first two seasons has been practically identical. In other words, while it might seem like he's spinning his wheels, Gordon subtly is learning, developing, growing. What I see is that he'll be 25 years old and with more than 300 career games under his belt, in all likelihood, entering 2009. That's often just the right experience level for a player to begin to really flourish as a hitter.

Phil Hughes, SP, Yankees: Remember this guy? Hughes has been somewhat forgotten in fantasy, thanks to being overshadowed by Joba Chamberlain's successful transition to the rotation (current shoulder injury notwithstanding) and his terrible April before hitting the disabled list with a stress fracture in his rib cage. Hey, at least it wasn't an arm problem, which is better than we can say for Chamberlain. Hughes is on the comeback trail, having tossed 6 2/3 scoreless innings with a .136 batting average allowed in two rehabilitation starts for Class A Charleston, and now he's at Triple-A Scranton/Wilkes-Barre, finishing his rehab. It might not be long before people are saying, "Oh yeah, that Hughes guy, he was supposed to be pretty good, right?" That's why now is prime time -- and I mean career-wise, not necessarily for 2008 -- to snatch Hughes up on the cheap. His value could not possibly be lower, and the brief glimpses we saw of him in 2007 demonstrate a ceiling of top-of-the-rotation potential, with his floor no worse than middle-of-the-rotation. In fact, I'd put the odds at about 50/50 that he offers at least those No. 3/4 starter-type numbers in 2009, with the 50-percent against almost entirely a result of health concerns. And that's a chance well worth taking.

Adam Jones, OF, Orioles: It's entirely possible that his season is over due to his fractured left foot, and even if it's not, it'd be shocking to see him back in action before Sept. 1. Either way, a contending keeper-league team can't afford to wait four-plus weeks on a player on pace for 10 home runs, 12 stolen bases and fewer than 80 RBIs or runs scored. That's the bad with Jones; the good is that he possesses both power and speed upside, maybe as much as double those numbers in 2009.

Kevin Slowey, SP, Twins: I'm pretty big on pitchers with extraordinary minor league statistics, and Slowey sure had them, with a 1.94 ERA and 0.85 WHIP for his career. Plus, he has made some important strides this season, most notably cutting his home runs from 2.16 per nine innings a year ago to 1.31. Now, if he can only get that number even halfway from there to his 0.49 minor league number, we'd have a potential ace on our hands. I see Slowey's 1.10 WHIP and wonder whether keeper-league owners know how rapidly this guy is developing. He might be a low-WHIP 2009 sleeper like Dave Bush was in 2007 ... only Slowey will actually make good on the forecast.

Justin Upton, OF, Diamondbacks: Of all the names on my list, he's the one I'm least bullish on for 2009; that is, for 2009 alone. For 2010 and beyond, he might qualify as the one I find most appealing, so take that for what it's worth, depending on your league's keeper system. Upton is a future MVP candidate, and was deemed the No. 2 prospect in the game by Baseball America in 2006, behind only Delmon Young. By the way, look at Young; he's averaging nearly 60 at-bats per home run (58.7) for his career. Upton? He's at 32.1, noticeably better, despite being 23 months younger. He's a little ways away from reaching his statistical peak, but he's going to get there sooner than Young. When that happens, he'll cost you certain first-round value. But today, there's a chance he'd cost you the relatively cheap price of a seven-week rental.

Ryan Zimmerman, 3B, Nationals: People are beginning to forget about this guy, partly because he has missed so much time with a shoulder injury, partly because he slipped somewhat statistically in 2007 from his stellar rookie-year numbers, and partly because he plays on a team that, frankly, has been awful. As such, it's easy to forget that this kid is still 23 (he'll turn 24 on Sept. 28), with a lot of career ahead of him. A winter's rest -- or perhaps surgery with a mere 3-4 month recovery period -- should do him worlds of good, and really, this is a franchise talent most people treat like a short-term fix. Folks, this is the worst it gets with Zimmerman. Maybe he's not a perennial MVP candidate, but those Brooks Robinson comparisons are not at all unfair.

Tristan H. Cockcroft covers fantasy sports for ESPN.com. You can e-mail him here.