Ranking atm:
1. Samsung Khan 12-7 +6
2. SK Telecom T1 11-8 +12
3. KT Rolster 11-8 +11
4. Woongjin Stars 11-9 -3
5. CJ Entus 10-9 +3
6. STX SouL 9-11 -7
7. Team 8 7-11 -6
8. Airforce ACE 5-13 -18
As of right now, STX SouL, Team 8, and Airforce ACE have been eliminated and there's no way these teams will qualify for the playoffs (every team plays 21 games. STX SouL's best record, as well as Team 8's, could be 10-11 at this point, which will be still lower than current 4th place's (Stars) record in terms of win/loss).
Now, we only have 5 teams left.
1. Samsung Khan.
Although Khan's leading at the moment with 12-7, they still have two matches to go. They're against Team 8 and Woongjin stars. Given that, if they win one more game they will secure a place in playoffs. If they lose both games with 0:3, then they will be TIED with Woongjin Stars (because if Khan loses 0:3 both games, it means they're down to +0. If Stars win with that score, they're also back up to +0, which means they will be tied).
Bare Minimum For Playoffs: Khan wins one set, secures playoff (see the worst case scenario for explanation).
Worst case scenario: Khan loses twice 0:3, ties with Stars and CJ wins both games while SKT and KT wins at lease once, putting Khan in 4~5 spot with Stars (In this case, I don't know what happens but I'm pretty sure Khan will lose their spot in playoffs, or have a wildcard match or something).
2. SK Telecom T1
SK Telecom T1 has 2 games left: one against Airforce ACE and one against Team 8. Since their difference is +12, one win can put them in a playoff spot (even if CJ goes +6, that is +9 at maximum for CJ. SK Telecom T1, if they win once, can go down to at least +10 (+1 then -3), but not further below). If SK Telecom T1 loses both games, then it will depend on Stars, CJ, and KT's record to see if SK Telecom can advance or not.
Bare Minimum For Playoffs: SK Telecom T1 wins once, secures playoff.
Worst case scenario: SK Telecom T1 drops both games, putting them in 11-10 while Stars win their last match and CJ wins both of their matches, putting SKT below both teams. THEN they need KT to lose both games respectively and make sure that the total difference is higher than KT's.
3. KT Rolster
Similar situation with KT Rolster, though they need to watch out a little bit more if CJ goes +6 as they might be tied with CJ Entus if KT ends up with -2 in their last 2 matches (given that KT wins and loses, or vice versa). If they win twice, they secure a playoff position as Stars and CJ both have 9 losses. If they win and then lose with only -1 difference for both games or higher, they secure a spot. If they lose both games, it depends on how well CJ, Stars, and SKT does.
Bare Minimum For Playoffs: KT Rolster wins once and have difference of -1 or higher in last 2 games, secures playoff.
Worst case scenario: KT Rolster drops both games, putting them in 11-10 while Stars win their last match and CJ wins both of their matches, putting KT below both teams. THEN they need SKT to lose both games respectively and make sure that the total difference is higher than SKT's.
4. Woongjin Stars
This is where it gets interesting. Stars is in a huge trouble. Although they lead CJ Entus in terms of win/loss, their difference is -3. Stars have one final battle against Samsung Khan this season, and they need to win that game in order to have a good chance at going to playoffs. If they win, CJ has to lose one match and/or KT or SKT have to drop both of their games in order for a playoff spot. If they lose, CJ NEEDS to lose both of their games. HOWEVER, if CJ wins twice, Stars need to depend on KT or SKT to drop both games because they will fall behind CJ in terms of win/loss ratio. In this scenario, Stars HAVE to win against Khan. If KT or SKT goes 1-1, they will have same record as Stars. However, since the biggest difference you can get from 1-1 is -2 and since both KT and SKT are in double digits while Stars can only bring up their difference to +0, Stars need KT and/or SKT to lose both of their remaining matches.
Bare Minimum For Playoffs: Stars win against Khan, THEN CJ loses once and/or KT/SKT loses both of their games.
Worst case scenario: Stars loses, CJ HAS to lose both of their games in order to have a chance.
Worst case scenario 2: Stars wins but CJ wins both of their remaining games. Stars need KT or SKT to drop both games or they're out.
5. CJ Entus
CJ Entus, although behind on rankings, can catch up to Stars pretty quickly since they have two matches to go (instead of Stars, since they only have one match left). Best case scenario is that they win twice; that will put them in a playoff spot easily. If they lose one of two games, Stars needs to lose their game against Khan or it's over for CJ Entus. However, if CJ loses twice it's completely over (10-11 in record while Stars' worst case scenario is 11-10). Now, why did I say that CJ can win twice to secure a spot in playoffs? Let's look at the difference. Though Stars is leading CJ, they have -3 while CJ has +3. This means that if CJ wins twice, the worst possible difference they can end up with is +5 (+1 then -1). Stars, on the other hand, can only end up at +0 (3:0 against Khan). Similar situation with one win one loss situation for CJ and Stars losing against Khan. If they win once but drop one, they can go down to +1, but not any further. Stars, on the other hand, will stay at negative numbers, giving up their spot to CJ Entus. SK Telecom T1 and KT Rolster can also fall below CJ if either one of the teams lose twice then CJ wins twice, but SKT and KT needs to lose huge in both games and CJ needs to win big in both games (talking about complete shutouts here). However, since Khan has only +3, they can fall easily below CJ if they drop both games (CJ can only go up from +3, while Samsung goes down from +6 with same 12-9 record if CJ wins twice and Khan loses twice. That means Samsung, at most, will have +4 while CJ, at least, will have +5). Realistically, CJ still has a chance on securing a playoff spot.
Bare Minimum For Playoffs: CJ wins twice, secures playoff spot no matter how well Stars does at the end of the season.
Worst case scenario: CJ loses twice, will not qualify for playoffs.
What's more interesting in this race, is that all of the remaining matches are playoff-hopefuls versus knocked out teams, with the exception of Samsung Khan vs Woongjin Stars.
I've never seen any race this close in Proleague until now. Not one team has secured a playoff position as of this moment, and no team is safe from getting eliminated. It's going to be interesting few days, as post-season begins on the 17th with the last game being played out on the 14th.
Disclaimer: I wrote this very quickly without any charts, graphs, or whatsoever. If you need more clarifications, find any mistakes in the possible situations as well as ones that weren't explored, or have anything to add to this in general please feel free to comment.