For the fourth straight year, ESPN.com and the TrueHoop Network are ranking every NBA player and counting them down on Twitter (@ESPNNBA) from No. 500 to No. 1.

We asked our ESPN Forecast panel to predict the overall level of play for each player for the upcoming NBA season. This includes both the quality and the quantity of his expected contributions, combined in one overall rating.

As the rankings are announced, you also can find them here on the pages of ESPN.com.

The players on our list keep getting better and better. We're counting down five more players Tuesday, revealing them one at a time on Twitter. We'll continue the countdown until Oct. 28, opening night in the NBA. Today we roll out players 21 through 25.

Tim Duncan is 96 points away and 168 assists away from joining Kareem Abdul-Jabbar, Wilt Chamberlain, Karl Malone and Kevin Garnett as the only big men to accumulate at least 25,000 points and 4,000 assists in their careers.

-- ESPN Stats & Information (@ESPNStatsInfo)

@ESPNNBA Death, taxes and a double double from Tim Duncan. When asked in playoffs, still plays at elite 20+. 10+ level for @spurs #NBArank - Pavle Kisin-Rajlic (@Gambitguru77) October 21, 2014

@ESPNNBA its hard to believe Timmy is JUST getting to 25,000pts. He is the ultimate team athlete. #NBArank - Chicken & Beard (@msiraji29) October 21, 2014

22

7.88

Al Jefferson | @hornets

Charlotte Hornets | C | Age: 29 | 2013 rank: #52

Al Jefferson led the NBA with 11.0 post-up points per game last season and was second in the NBA with 13.5 paint points per game.

-- ESPN Stats & Information (@ESPNStatsInfo)

@ESPNNBA At least 22 Centers will be put in Big Al's torture chamber this year. Best footwork in the NBA. #NBArank #BigAl #LeftBlock - Matt Levine (@MattLevine66) October 21, 2014

23

7.88

Kyrie Irving | @KyrieIrving

Cleveland Cavaliers | PG | Age: 22 | 2013 rank: #8

Kyrie Irving has averaged at least 18 points per game and 5 assists per game in each of his first three seasons. Only Oscar Robertson, Magic Johnson, LeBron James, Grant Hill and Steve Francis have accomplished that feat.

-- ESPN Stats & Information (@ESPNStatsInfo)

@ESPNNBA Time for Irving to stay healthy and live up to his potential. Scoring 23 ppg to match his rank would be a great start #NBArank - Steven Couper (@CouperSteven) October 21, 2014

24

7.84

Kawhi Leonard | @kawhileonard

San Antonio Spurs | SF | Age: 23 | 2013 rank: #34

Kawhi Leonard was one of four players last season to average at least 12 points per game, shoot 50 percent from the field and 35 percent from the 3-point line (minimum two 3-point attempts per game). The other three players were Kevin Durant, LeBron James and Goran Dragic.

-- ESPN Stats & Information (@ESPNStatsInfo)

#NBArank Kawhi Leonard is a big game player, but he won't average more than 18 per game. Does everything well but he's just not that guy — fracca (@sandrofracca) October 22, 2014

25

7.81

Serge Ibaka | @sergeibaka9

Oklahoma City Thunder | PF | Age: 25 | 2013 rank: #39

Serge Ibaka led the league in blocks (219) last season for the fourth straight season. Only Dikembe Mutombo had a longer such streak in NBA history (five straight, 1993-98).

-- ESPN Stats & Information (@ESPNStatsInfo)