There are certain NHL prospects who can be safely penciled into opening night lineups. First-overall pick Macklin Celebrini will have zero competition in San Jose. Matvei Michkov excelled against men in the KHL and will waltz into a Flyers' lineup desperate for talent.
Most prospects will not enter the season with a presumed lineup spot. If you're not clearly ready for a prominent role entering training camp, then you're likely fighting for a spot down the depth chart. Teams tend to have veterans on hand for those positions and the onus falls on the youngsters to seize their spot on the roster.