Baseball Commissioner Bud Selig said Wednesday that his sport’s suspension of 13 players earlier this week for using performance-enhancing drugs was “a good day for baseball,’’ and he is particularly gratified that so many players have supported the penalties.

Selig was at Target Field to deliver the keynote address at a luncheon for young players participating in the Reviving Baseball in Inner Cities (RBI) world series, which is being hosted by the Twins. At a news conference following the event, Selig addressed reaction to the punishments handed down Monday. Yankees star Alex Rodriguez was suspended through the 2014 season but will continue playing while he appeals the penalty; the players’ union filed his formal appeal Wednesday. A dozen other players received 50-game bans.

Selig said the investigation that led to the suspensions was a difficult, stressful time for him. He added that he is proud that many players have voiced approval of the sanctions, and he insisted that baseball has “the toughest drug-testing program in American sports,’’ though he noted there will be future discussion on whether harsher penalties are needed.

“The players have been very outspoken, and I don’t blame them,’’ Selig said. “I felt badly years ago, and I had players come and talk to me. I had one player who said, ‘Steroid era? I didn’t do it.’

“The great majority of our players have done this well and clean, and they don’t like being tarred with this. I understand that, and I’ve heard from a fair number of players. They’re very supportive of what we’ve done, and that means a lot to me.’’

Selig said baseball had an obligation to take action against performance-enhancing drugs because it is a social institution held to a higher standard. He said he is proud that 13 players accepted the suspensions, and when asked if he was comfortable with Rodriguez playing during his appeal, he said Rodriguez “has a right’’ to do so. In addition to the players’ backing, Selig noted that several team trainers have expressed satisfaction with the sanctions, and team owners have called to congratulate him.

The commissioner also sounded a warning that the fight is not over. He said baseball has begun using “longitudinal testing,’’ a more sophisticated method of drug detection that should catch more users.

On Tuesday evening, Selig said, he watched several games; for the first time in a long while, he was able to simply enjoy the action on the fields. After an investigation that consumed most of the past six or seven months, he said he is satisfied that “no stone was left unturned,’’ and that same effort will continue.

“There was a big debate Monday and Tuesday, is this a good day or a bad day for baseball?’’ Selig said. “It’s not even a question. It was a good day for baseball, because we faced up to the problem. Nobody’s hiding it. Nobody swept it under the rug.

“The most important thing to me is, we’re doing what we said we would do 10 to 12 years ago … Nothing is perfect. But the fact is, I think we’ve done everything we can.’’