Fleury stopped all eight shots he faced during the third period of his final game with the Penguins, a 4-1 preseason win over the Blue Jackets on Saturday night.
The 22-year-old McTavish was a restricted free agent, and he didn't report to camp with the rest of the Ducks on Sept. 18 after negotiations dragged on his new deal.
Fowler has been a strong fit since the Blues acquired him from the Ducks in December. He had 36 points in 51 games last season to help St. Louis make the playoffs.
The 40-year-old officially retired from the NHL as a member of the Minnesota Wild in the spring but signed a professional tryout contract with the Penguins earlier this month.
Defenseman Alex Pietrangelo has not ruled out playing again for the Golden Knights -- even this season -- hoping to avoid surgery as he goes through rehabilitation on his injured hip.
He won Stanley Cup, Conn Smythe and Vezina trophies in back-to-back seasons when the Flyers captured the Stanley Cup in 1974 and 1975, the first NHL expansion team to win the championship.