Captains can select teams after toss in SA20 tournament

Also, there will be no overthrow runs if an "intentional" run-out attempt results in the ball deflecting off the stumps

Team captains - for the very first time in a premier T20 competition - can select their playing XIs after the toss is conducted. On the day before the inaugural SA20 competition begins in Cape Town, the organisers said that this possibly revolutionary tweak, among a few other additions, has been included to "improve the quality of the product" while "preserving the sanctity" of the game.
Essentially, captains must nominate 13 players before the toss, and after the coin flip, are allowed to reduce their team size to 11. The two players left out will become the substitute fielders.
Another unique change to their playing conditions is that there will be no overthrow runs if an "intentional" run-out attempt results in the ball deflecting off the stumps. The organisers said this was to encourage "positive and attacking fielding."
There will also be a bonus point up for grabs in every game. Beyond the four points for a win, if a team can win with a run rate that is 1.25 times their opponents', they will earn a fifth point. Another change they've introduced is that there will be no run off a "free-hit" delivery if that ball hits the batter's wicket.
Among all these changes, the choose-after-toss rule will steal the spotlight. Never before has a reputed T20 competition made such a change to one of the fundamental laws of cricket. However, more recently leagues have not shied away from experimenting with changes to how the T20 game is played. The Big Bash League in Australia introduced "Power Surge" (powerplay overs split into 4+2), "Bash Boost" (bonus point for better score at halfway stage) and "X-Factor" (substitute player at over 10). Similarly, the IPL is introducing the "Impact Player" rule into the competition after completing a trial run in their domestic T20 tournament.
The SA20 competition starts January 10 with MI Cape Town playing at home against Paarl Royals. The 33-match six-team competition is part of a star-studded T20 line-up in January that includes the Emirates T20 League, the Big Bash and the BPL in Bangladesh.