As the NBA trade deadline approaches, it's time for fantasy owners to get their rosters in order for the stretch run and playoffs in head-to-head leagues. For those who play in keeper leagues, it's also time to think about the players you are going to be keeping for next season.

Everyone is looking for the definitive keeper league player list, but there are so many variations on keeper leagues and rules that it is impossible to make a single list that is applicable to all leagues. Player value in keeper leagues is really dependent on the makeup of the league, so it is important to take into account a few factors when deciding on which players to keep.

Know the rules: Keeper leagues are like snowflakes, every one is different in its own little way. They range from single-year leagues that allow teams to carry over players just once to the next season, all the way to dynasty leagues that allow teams to draft and lock up players for their entire careers. The type of league makes a big difference in how you should approach keeper selection. In a single-year keeper league you only have to worry about next season, so players on the wrong side of 30, such as Dirk Nowitzki, still make viable keepers. As the number of years that you can keep a player grows, it becomes more and more challenging to predict player value out into the future.

Go young, but not that young: Unless you play in a dynasty-type league that allows you to keep players for five or more years, don't ignore veterans with proven track records. Most of the time, top players in the league will maintain a high level of play even into their early-to-mid 30s. Studies suggest that the average NBA player peaks around ages 25-27, so a good rule of thumb for multiple-year keeper leagues is to focus your attention on players who are under the age of 30.

Avoid uncertainty: Much like the stock market, you want to maximize your return while minimizing your risk. One way to do that is to avoid players with chronic injury histories. It's obvious that Brandon Roy makes a bad keeper because of his knee injuries, but even players like Andrew Bynum carry additional injury risk long-term. Another way to avoid risk is to be careful of players with uncertain contract situations. The 23-year-old Wilson Chandler is in the middle of a breakout season for the Knicks, but he is set to become a restricted free agent this offseason. With the Knicks potentially either trading for or signing Carmelo Anthony, Chandler's future with the team and his fantasy value is currently up in the air.

Look for a track record: Young, unproven players with high upside are like lottery tickets. Your team is set if one hits, but it could leave you with nothing if that's all you invest in. In 2009, Anthony Randolph averaged 13.9 points, 11.1 rebounds and 1.4 blocks over the last 10 games of his rookie season. Unfortunately for everyone who decided to make him a keeper, it was the best stretch of basketball he's played in a career that's off to a disappointing start. If you are on the hunt for high upside keepers, look for players who have played consistently well in limited minutes, been stuck behind a more established player, or have had some bad luck that has held them back. Paul Millsap was a good example of someone who played well but was stuck behind Carlos Boozer in the Jazz rotation. With Boozer off to Chicago this season, Millsap has been a top 40 fantasy player. Next season, DeJuan Blair is a player who could breakout as Tim Duncan enters the twilight of his career. Serge Ibaka could also be in for a huge season if the Thunder trade Jeff Green, while Ty Lawson will eventually get his chance in Denver when Chauncey Billups retires.

Some keepers come with a price: Auction leagues often allow players to be kept based on the price paid for them in auction. It is common for keeper leagues with drafts to let teams keep a player and lose the corresponding draft pick in the following year's draft. For example, if Dorell Wright was drafted in the 10th round this year, he could be kept next year and the team would forfeit it's 10th round pick. In these types of leagues, the opportunity cost also becomes a factor when making keeper decisions. If you are making a decision between two similarly valued players, go with the one who costs less, either in terms of dollars or draft picks.

Here is our list of the top 25 long-term, multiple year keepers for 2010-11 (with current player age in parenthesis).

1. Kevin Durant (22), SF, Oklahoma City Thunder 2. LeBron James (26), SF, Miami Heat 3. Derrick Rose (22), PG, Chicago Bulls 4. John Wall (20), PG, Washington Wizards 5. Chris Paul (25), PG, New Orleans Hornets 6. Stephen Curry (22), PG, Golden State Warriors 7. Blake Griffin (21), PF, Los Angeles Lakers 8. Dwight Howard (25), C, Orlando Magic 9. Russell Westbrook (22), PG, Oklahoma City Thunder 10. Kevin Love (22), PF, Minnesota Timberwolves 11. Josh Smith (25), PF, Atlanta Hawks 12. Al Horford (24), PF/C, Atlanta Hawks 13. Joakim Noah (25), C, Chicago Bulls 14. Tyreke Evans (21), PG, Sacramento Kings 15. Eric Gordon (22), SG, Los Angeles Clippers 16. Rudy Gay (24), SF, Memphis Grizzlies 17. Deron Williams (26), PG, Utah Jazz 18. Rajon Rondo (24), PG, Boston Celtics 19. LaMarcus Aldridge (25), PF, Portland Trail Blazers 20. Amar'e Stoudemire (28), PF, New York Knicks 21. Monta Ellis (25), PG, Golden State Warriors 22. Andrew Bogut (26), C, Milwaukee Bucks 23. Danny Granger (27), SF, Indiana Pacers 24. Raymond Felton (26), PG, New York Knicks 25. Carmelo Anthony (26), SF, Denver Nuggets

Other contenders: Dwyane Wade (29), Dorell Wright (25), Paul Millsap (26), Wilson Chandler (23), Danilo Gallinari (22), Jrue Holiday (20), Brook Lopez (22), Andre Iguodala (27), DeJuan Blair (21), Andrea Bargnani (25), DeMar DeRozan (21), Wesley Matthews (24), JaVale McGee (23), Serge Ibaka (21), Roy Hibbert (24), Al Jefferson (26).

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