Peterson (31-2-1, 16 KOs) puts his IBF junior welterweight title on the line against undefeated No. 1-ranked contender Dierry Jean of Montreal at the DC Armory.
Peterson is coming off a third-round TKO loss to Argentina's Lucas Matthysse in a non-title fight last May in Atlantic City.
"I don't have any pressure on me. I don't feel like it's a must win or I have to prove anything," Peterson said a press conference on Thursday. "At the end of the day, I love boxing. That's why I'm going to fight Saturday night, because I enjoy it."
The 31-year-old Jean (25-0, 17 KOs) earned a title shot with a fourth-round TKO against Cleotis Pendarvis in an IBF elimination fight in May.
"I have the power, I have the chin, and I have the style," Jean said of his chances on Saturday night. "I need to hit at the beginning to remind him of the last knockout he had."
Peterson, 29, won the WBA and IBF titles from Amir Kahn by split decision in Washington in December, 2011. He was stripped of the WBA title after testing positive for synthetic testosterone before a scheduled rematch with Kahn in May 2012. The fight was canceled and Kahn was reinstated as WBA champion.
Peterson's camp said the test results stemmed from treatment for a medical condition.
He successfully defended the belt last February with an eighth-round TKO of Kendall Holt.
A dispute among the sanctioning bodies rendered his meeting with Matthysse, then the interim WBC champion, a non-title fight. Peterson was floored once in the second round and twice in the third before the fight was stopped.
"We train hard, we go in there to fight, we go in there to win, but we also know there's a chance that you could lose," Peterson said. "And that's what happened, and you just have to pick yourself up and move on."
Jean, who was born in Haiti, didn't begin boxing until he was 18. He turned pro in 2006 and is fighting for just the third time outside of Canada. Peterson will be his toughest competition thus far.
"I'm in the best shape of my life for this fight, for sure," Jean said. "I've been in training camp ... we have good sparring partners and I'm ready."
He said he can take advantage of Peterson's chin, but needs to be aware of the champion's reach.
Peterson said Jean has versatile skills.
"He's tough. He's got good speed, good power, he has everything that you look for in a fighter," Peterson said. "He's going to be a good challenge, but I think at the end of the day I'll come out as the victor."
The co-main event on the Showtime card features super welterweights Jermell Charlo of Houston (22-0, 11 KOs) and Gabriel Rosado of Philadelphia (21-7, 13 KOs) fighting for Charlo's WBC Continental Americas title.