PER is imperfect. It essentially ignores defense, and does not account that a solid impact over 30 minutes is better than the same impact over 10 minutes. However, it can show a pretty good idea of where a player is relative to their peers, and if a player's PER is lower, there's usually a very good reason, such as: inefficient scoring (low percentage, low drawing free throws, ineffective at 3s) or an ability to be on the court without picking up assists, rebounds, etc.
With that in mind, here are players listed as SF with better PERs than Green RIGHT NOW. So, who on that list will decrease below Green's current level OR who will Green pass to get to Top 5?? BTW, Greens max PER is 13.99 (year 2); a mythical perfectly average production player is 15.00.
Also, people will argue about whether certain players are truly SFs, trying to eliminate competition based on a technicality. Here are some SGs/PFs not on the list with better PERs than Green, so I think this method of arguing is a wash. (like asking "who's the best pure PG" then explaining why the best PGs aren't pure): Ginobili, JR Smith, Joe Johnson, Dudley, Gerald Henderson, Hayward, Carter, Derozen, Iguodala, Korver, Sefolosha. PFs: Villanueva, Derrick Williams, Darrell Arthur, Daye, Cunningham.
RK PLAYER PER
1 LeBron James, MIA 30.3
2 Kevin Durant, OKC 29.15
3 Carmelo Anthony, NY 25.29
4 Paul Pierce, BOS 19.09
5 Kenneth Faried, DEN 19.02
6 Andrei Kirilenko, MIN 18.63
7 Nicolas Batum, POR 17.74
8 Matt Barnes, LAC 17.69
9 Thaddeus Young, PHI 17.51
10 Paul George, IND 17.44
RK PLAYER PER
11 Josh Smith, ATL 17.11
12 Jordan Hamilton, DEN 16.91
13 Earl Clark, LAL 16.74
14 Danilo Gallinari, DEN 16.69
15 Ersan Ilyasova, MIL 16.53
16 DeMarre Carroll, UTAH 16.45
17 Shawn Marion, DAL 16.21
18 Chris Copeland, NY 16.11
19 Mike Dunleavy, MIL 15.95
20 Michael Kidd-Gilchrist, CHA 15.73
RK PLAYER PER
21 Luol Deng, CHI 15.22
22 Corey Brewer, DEN 15.17
23 Rudy Gay, MEM 14.64
24 Jimmy Butler, CHI 14.63
25 Chandler Parsons, HOU 14.54
26 Kawhi Leonard, SA 14.35
27 Metta World Peace, LAL 14.19
28 Dorell Wright, PHI 14.12
29 Al-Farouq Aminu, NO 14.03
30 Tobias Harris, MIL 13.88
RK PLAYER PER
31 Gerald Wallace, BKN 13.72
32 Evan Turner, PHI 13.38
33 Tayshaun Prince, DET 13.31
34 Martell Webster, WSH 13.23
35 Carlos Delfino, HOU 13.15
36 John Salmons, SAC 12.47
37 Mike Miller, MIA 12.3
38 Moe Harkless, ORL 12.27
39 Omri Casspi, CLE 12.21
40 Trevor Ariza, WSH 12.15
RK PLAYER PER
41 Francisco Garcia, SAC 12.04
JEFF GREEN 11.93
42 Caron Butler, LAC 11.75
43 C.J. Miles, CLE 11.54
44 Harrison Barnes, GS 11.53
45 Jae Crowder, DAL 11.44
46 Steve Novak, NY 11.21
47 Alonzo Gee, CLE 11.01
48 Kyle Singler, DET 10.52
49 Ronnie Brewer, NY 10.47
50 Quincy Pondexter, MEM 10.38
So, in 2 years, who does he pass without anyone passing him (younger guys/current highschool or college guys)??