Each player can become an unrestricted free agent July 13.
"I think you look at them individually, they've both been here 16 years," Hextall said. "'Geno' has obviously been a great player, certainly one of the best players in the history of the game. We'd like to keep him as a Pittsburgh Penguin for the rest of his career.
"In a perfect world, Geno retires a Penguin. I think 'Tanger' is the same. They've been here the same amount of time. These two, they're generational players. They don't come around very often."
Malkin, who completed the final season of an eight-year, $76 million contract, has played 981 games, second in Penguins history behind Sidney Crosby (1,108), since being selected with the No. 2 pick in the 2004 NHL draft. The 35-year-old center is third behind Mario Lemieux and Crosby in goals (444), assists (702) and points (1,146).
Letang, who finished the final season an eight-year, $58 million contract, is third in Penguins history with 941 games since being selected in the third round (No. 62) of the 2005 NHL Draft. The 35-year-old is first among defensemen in their history in goals (144), assists (506), and points (650).
Pittsburgh has qualified for the Stanley Cup Playoffs in each of its 16 seasons with Malkin and Letang, including winning the Cup in 2009, 2016 and 2017.
Last week, Malkin said he would like to play another three or four seasons in the NHL, hopefully with the Penguins.
"I understand it's a business," Malkin said on May 17. "I love this city. I love these fans so much. If the team wants new blood, young guys, and say to me, 'You should move on,' I'm fine. … I hope I stay here forever, like retire here."
Letang said he could play another "four, five years. Easily."
"It's always been the main goal, to stay here and play in Pittsburgh," Letang said. "I certainly tried to build something good here. Just want to keep it going."
Hextall did not disclose what length of contract the Penguins would be comfortable offering each player.
"Those talks are internal," he said. "What I can tell you is they're both great athletes. They've both been here a long time. They're both performing at a high level right now. We'd certainly like to have them in the mix in September."
Signing Malkin and Letang would help the rest of the roster take shape, Hextall said. Forward Bryan Rust agreed to a six-year, $30.75 million contract ($5.125 million average annual value) on Saturday.
"It's tough when you go from the top and build your way down," Hextall said. "We'll see where guys like Tanger and Geno end up, and we'll figure the rest out from there. … We would like to keep them here through the end of their careers. Obviously, we have some issues in areas we have to work through in terms of the salary cap.
"Everything has to match up. It's a puzzle right now. I wish we had more pieces in place to make it a little more clear, but it's hard to even venture a guess where we'll end up."
Letang had an NHL career-high 68 points (10 goals, 58 assists) in 78 games this season. Malkin had 42 points (20 goals, 22 assists) in 41 regular-season games and six points (three goals, three assists) in the playoffs, when the Penguins were eliminated by the New York Rangers in seven games in the Eastern Conference First Round.
The Penguins could bring someone in free agency to center the second line if Malkin can't be retained, Hextall said. For now, though, their goal is to have Malkin return for a 17th season.
"First and foremost, we would like to sign Geno, so we'll work through that," Hextall said. "If at some point we realize that can't happen, then we'll certainly look elsewhere. But right now, our focus is on Geno."
