Cam's shoulder was already an issue in 2018, that was just the final nail in the coffin. I think even before the injury they had to rest his should following the 2017 surgery, and Heinicke had to come on at least once to attempt a Hail Mary pass instead of Cam. Cam was still effective as the offense relied less on deep throws and more on quick passes on short and intermediate routes which brought his completion percentage at its highest in career before the TJ Watt hit.