No — there is no reliable public source that currently confirms Ralph Sampson is left-handed.

Ralph Sampson is an American former professional basketball player who played in the National Basketball Association (NBA). Standing at 7 feet 4 inches, he was one of the tallest players of his era and was known for his exceptional skill set for a player of his size.

Sampson was a three-time National Player of the Year in college at the University of Virginia before being selected as the first overall pick in the 1983 NBA draft by the Houston Rockets. He was named the NBA Rookie of the Year in 1984.

He formed a formidable duo with Hakeem Olajuwon, known as "The Twin Towers," leading the Rockets to the 1986 NBA Finals. Sampson was a four-time NBA All-Star and was inducted into the Naismith Memorial Basketball Hall of Fame in 2012.

Despite a career hampered by injuries, Sampson's impact on the game was significant, showcasing a unique blend of size, agility, and shooting touch that redefined the center position.