Selig spoke a small group Wednesday at a sport and society conference at St. Norbert College.
Previously reluctant to add replay, Selig instituted it in August 2008 for boundary calls on potential home runs, such as whether balls went over the fence or were fair.
MLB sought to increase video review this season to include trapped balls, fair-or-foul rulings down the lines and fan interference all over the ballpark. But it requires approval of MLB and the unions representing the umpires and the players, and any expansion was delayed until 2013 at the earliest.
''I've had very, very little pressure from people who want to do more,'' Selig said.
Selig indicated adding replay for balls hit down the line - ''bullets, as I call 'em'' - and trapped balls may be ahead.
Selig again repeated his oft-spoken - and oft-ignored - intention to retire. Selig, who turns 78 in July, has been commissioner since 1992. His term was extended again in January through 2014.
Though virtually no one in baseball believes him, Selig says this is his last extension.
''Number one, I'd have to convince my wife, and number two, I do want to teach,'' he said. ''That'll take me to age 80. I would think then you better send somebody to get me because this is it. I will say that.''
If he stays until September 2016, he would surpass Kenesaw Mountain Landis (1920-44) as the longest-serving baseball commissioner.
Selig has been teaching sports law at Marquette University Law School in his native Milwaukee the last four years. He hopes to teach a course on sports in American society at University of Wisconsin in Madison next year.
Selig said MLB will have revenue of $7.5 billion this year, dwarfing the $1.2 billion when he took over as acting commissioner.
He was looking forward to Wednesday night's matchup between Philadelphia and Washington.
Cole Hamels is scheduled to make the start for the Phillies against teenage rookie Bryce Harper and the NL East-leading Nationals. Hamels drew a five-game suspension for deliberately hitting Harper with a pitch on May 6.
''I think it's going to be very interesting when Harper comes up (to bat),'' said Selig, eliciting laughter from his audience at the college.
Selig then referenced Hamels' postgame admission of intentionally plunking Harper.
''Sometimes, some things are better unsaid,'' Selig said. ''But I have to let that thing play out. I think the discipline was fair. I think we handled it well. Cole Hamels has been great since then. Harper's been good. Both clubs have been good. I didn't hear from either club.''