The San Francisco 49ers have multiple players that can boom in fantasy football but are also unpredictable. Kyle Shanahan‘s use of a running back committee creates a hard to predict backfield. George Kittle, Deebo Samuel, and Brandon Aiyuk could take production away from each other making it challenging to foresee their success in 2021. The 49ers drafted Trey Lance and Trey Sermon in the offseason, which adds even more unpredictability to the team. Let’s take a look at what to expect from each 49ers’ fantasy-relevant players. Make sure to check out all of our other 2021 Fantasy Football Previe…