"We've thought about it. ... We've had very, very preliminary discussions with the Players Association about that," Silver said, per Kristian Winfield of SB Nation.
Adding additional rounds to the draft would likely be aimed at the G League. The NBA expanded rosters to include a pair of "two-way" players per team in 2017-18 and is aiming to have a 30-team minor league system in place in the near future.
Draft changes must be collectively bargained, and it's likely an expansion would result in some trepidation from players. As it stands, undrafted players can play for multiple summer-league outfits and assess their best fit. There is almost an advantage to being undrafted versus being taken with a late second-round pick.
The easiest concession the league could make is the guaranteeing of second-round contracts. As it currently stands, only first-round picks have the first two years of their contracts guaranteed. Second-rounders must negotiate with their teams and often wind up signing deals that heavily favor the club.
The Philadelphia 76ers under former general manager Sam Hinkie were infamous for these option-heavy contracts for second-round or undrafted players. Robert Covington saw his 2017-18 salary increase by $15 million when he renegotiated his four-year, $62 million extension. TJ McConnell, another Sixers rotation player, is facing a $1.6 million team option for next season because of a deal he signed coming out of college.
These Hinkie-type contracts expanded a bit around the league before agents began pushing back. Finding a guarantee structure for at least second-rounders may make the Players Association more willing to discuss adding a third or fourth round to the draft.
As it stands now, there's no real benefit from a player perspective. Third- or fourth-rounders would be unlikely to see much (if any) guarantees and be beholden to one franchise rather than having their pick.
NBA draft rights also carry over if a player chooses to continue his career overseas, so a guy who stars in Europe after being a third- or fourth-rounder could wind up being attached to one team instead of negotiating on the open market.