James, who jilted the Cavaliers to jump to the Heat this summer, may attend Saturday's game at Ohio Stadium between No. 12 Miami and second-ranked Ohio State.
Tressel said Thursday that it was time to let go all that anger.
"Sore subjects need to pass," Tressel said at a news conference. "Things are as they are. We all make decisions. You have to respect one another's decisions and move on."
On some message boards and college football sites, angry fans have said they do not want James coming to the game. Some have hinted at violence.
James communicates with Ohio State quarterback Terrelle Pryor, who also urged fans to welcome the former Cavaliers guard.
"If LeBron does come, just treat him with respect and respect his decision," Pryor said. "Please, no name calling, or booing, or anything like that because that's my mentor. I have a lot of respect and a lot of love for him."
James, who grew up in Akron, did not play college basketball. But he has said that if he had not jumped directly to the NBA, he would have attended Ohio State.
"He's a Buckeye," Pryor said of James' rooting interest in the game pitting the Buckeyes against the team from his new hometown, the Hurricanes.
Tressel joked that James had been an Ohio State fan for years.
"I think LeBron committed to me back when he was a junior," he said with a laugh. "I think we're in good shape."
After James announced that he was leaving the area where he grew up to join Dwyane Wade and Chris Bosh with the Heat, there was an immediate backlash from irate fans. Some burned James' No. 23 jersey.
Pryor, who called James "my main man, my mentor," said he always defended James.
"When he was down and people were burning his jersey, I just picked him up and said I'm with you 100 percent," he said he told James.
James and Pryor have been friends for years, frequently trading texts and e-mails. James stood on the sidelines at Ohio Stadium for the 10th-ranked Buckeyes' game against No. 3 Penn State on Oct. 25, 2008. Pryor failed to convert on a keeper on fourth down late in the game, leading to a 13-6 defeat.
"I told him I owe him a show," Pryor said.