With Evgeni Malkin added in once he recovers from a dislocated shoulder - he turned 20 slightly more than two months ago - the Penguins may have their youngest roster in their 40-season history as they try to bounce back from four consecutive last-place finishes.
Staal, who turned 18 last month, was the No. 2 pick in the June draft and still could wind up playing most of the season with the OHL's Peterborough Petes in junior. But with Malkin likely to miss the first few games of the season, the 6-4, 215-pound Staal gives the Penguins depth, size and a scoring threat at centre until Malkin returns.
"I hope I can be here for years to come," said Staal, the younger brother of Stanley Cup champion Carolina Hurricanes star Eric Staal and prospect Marc Staal of the New York Rangers.
For now, his service time may last only a few weeks, or until the Penguins determine if he is in over his head.
Letang, a 19-year-old defenceman and the Penguins' second-round pick behind Crosby in 2005, and Staal can appear in up to nine games before their three-year, entry-level contracts kick in.
Staal had 28 goals and 40 assists in 68 games last season for Peterborough while Letang had 25 goals and 43 assists in 60 games for Val d'Or of the Quebec Major Junior Hockey League.
Letang is more of an offensive force than he is a defender, much like Penguins defenseman Sergei Gonchar.
"I wanted to make the team when I came to camp," said Letang, who was given little chance of doing so when the Penguins' rookies reported nearly a month ago.
Coach Michel Therrien also announced that Marc-Andre Fleury, the No. 1 pick in 2003, will start Thursday's season opener against Philadelphia. The 21-year-old Fleury was inconsistent throughout training camp before stopping 25 of 28 shots in a 4-2 exhibition loss Saturday to Buffalo.
"We have a lot of confidence in the kid, even though during training camp he was not quite sharp," Therrien said.
For now, the Penguins will carry three goalies in Fleury, Jocelyn Thibault and rookie Dany Sabourin. They risked losing Thibault or Sabourin on waivers if they tried to send either back to the minors.
Thibault signed with the Penguins last season to be their starter, only to have a 1-9-3 record and a 4.46 goals-against average in 16 games. He missed most of the season after tearing cartilage in his left hip, allowing Fleury to become the primary starter.
Fleury had an excellent first month in the NHL at age 18 after being drafted in 2003 but has been inconsistent since, though he has yet to play a full season in the NHL. He was 13-27-6 with a 3.25 goals-against average in 50 games last season and 2-3 in five playoff games with Wilkes-Barre/Scranton (AHL).
The Penguins reassigned five players to Wilkes-Barre: forwards Daniel Carcillo, Libor Pivko, Ryan Stone and Maxime Talbot and defenseman Noah Welch. Welch had a goal and three assists in five Penguins games last season, spending most of the season at Wilkes-Barre.