With an offense filled with superstars and budding talents like Trent Williams, George Kittle, Deebo Samuel, and Brandon Aiyuk, an argument can be made for any one of them as the most irreplaceable player.
Williams is the best left tackle in the game. Kittle dominated in 2018 and broke receiving records. Samuel had an unprecedented season in 2021 as he carried and willed the 49ers into the NFC Championship game. Aiyuk is on the brink of a breakout season in a contract year.
Christian McCaffrey is the answer. His impact was immediate, and regardless of the quarterback, the offense started rolling as McCaffrey became more and more comfortable.