Malkin, 35, has scored 40 points (19 goals, 21 assists) in 40 games since returning Jan. 11 from having knee surgery June 4. Letang, 35, has tied his NHL career-high of 67 points (nine goals, 58 assists) in 77 games.
Crosby's 1,107 games played are the most in Penguins history, ahead of Malkin (980). The centers are second and third in team history in goals (Crosby, 517; Malkin, 443), assists (Crosby, 892; Malkin, 701) and points (Crosby: 1,409; Malkin: 1,144).
Letang has the most goals (143), assists (506) and points (649) by a Penguins defenseman.
"The reality is we're in a business where change is inevitable," Sullivan said. "It's part of what we all sign up for. I think, with respect to these guys and what they've accomplished, and the legacies that they've built here in Pittsburgh, it's impressive. They're deserving of the recognition that, just based on what they've accomplished, when I look at this core group of players, I believe they're the best core, in my mind, that I've ever been around."