Adapted from baseball, the new rule, which has been contemplated by the BBL for the past few summers, will permit teams to pick players who are allowed to bat without being required to field.
It could help prolong the careers of older batters, such as Adelaide Strikers' record run-scorer Chris Lynn or Perth Scorchers star Mitch Marsh, if they don't also have to strain themselves in the field.
There is also the potential for the new rule to tempt battle-weary Test players like Travis Head to play BBL more frequently.
Head starred in Australia's comprehensive Ashes victory, but won't feature in the BBL this season.
Australian cricket great Ricky Ponting backed the new rule, saying it could be used as a development tool for younger players in the field while keeping high-profile experienced batters in the competition.
"Some of these guys might be at a stage of their career where they feel that they can't make much of an impact (in the field)," Ponting said on Seven.
"They also might be worried about picking up an injury while they're in the field, which is another big part of it.
"And what this tournament doesn't want is to have these guys not playing, especially at this stage of the tournament when the big games are coming around.
"We all want to be seeing the best players playing, so if this rule helps that and keeps the longevity up, then that's great."
Importantly, designated batters and fielders will not be allowed to bowl, though a designated fielder can play as the wicketkeeper.
If teams choose not to select a designated batter, they will name a standard playing XI.
"It adds something to the tournament," Melbourne Stars allrounder Glenn Maxwell said on Seven.
"It will be interesting to see how it plays out though next year."
BBL player acquisition and cricket consultant Trent Woodhill said the new rule will create a fresh layer of strategic decision-making for clubs, both on and off the field.
"Feedback from players around the world to the concept has been very positive," Woodhill said in a statement.
"They know what a great experience a summer in Australia is and we anticipate this rule will help to attract even more top-tier talent next season."
The new rule does not yet apply to WBBL, with the league to continue reviewing its possible application in the women's competition future seasons.
