"It will be a subject they'll discuss during the next collective bargaining," Selig said. "I understand that individuals have a right to make their own decisions. I hope we're successful, because the Tony Gwynn story was a heartbreaking, awful story.
"I feel very strongly about this, just as I did 10, 15 years ago. The one thing I personally assume as commissioner is that we're responsible for the health of our players. I believe that. Some may think that's naive, but I don't think so."
Clark also recounted his friendship with Gwynn during his 45-minute media session.
"Tony impacted all of us in different ways," Clark said. "I was very fortunate to grow up in San Diego and have the opportunity to watch him play, and I had the privilege of playing against him on the field. So there's a personal connection there. His passing hurt a lot of us.
"With respect to tobacco itself, there are a number of players who made a decision [to quit] as soon as Tony passed. It really smacks you between the eyes. But truth be told, it's a process, and it takes time for some guys to wean themselves off or make whatever adjustment they need to make.
"Everything is negotiable. We can have that conversation with Major League Baseball. But our hope is that the trend we've been on will continue and we can ultimately get to a place where [players] leave [tobacco] alone."