Why would a player perform better as a bench player than a starter? It's not strictly a "matchup" thing becuase I've seen it over several years on different teams with very solid players. Even if the player has good matchups against the starters, there are certain guys who seem to perform better as bench players. The inverse is also true, but I figure that has to do with the character of the player (team vs. me guys) but there shouldn't be a converse effect.

It could be that they benefit from the increased distribution they get from playing with more subs than starters. It could also be a stamina thing; if they have low stamina they may be forced into playing more tired as a starter in close games. It could also be the extra time playing in blowouts against the scrubs of bad teams. Or it could just be randomness.

I'll add on to the stamina point, a few seasons back on 1 of my teams near the end of the season I brought a senior off the bench in favor of a sophomore because the senior had stamina in the 60s. What resulted was the senior playing much better off the bench because of less minutes and him not being tired and as a result my team played much better.

HD is also not 5 separate games of 1-1. Even if a starter has a favorable matchup, the other four defenders influence to some degree his results.

Coming off the bench and playing primarily against a backup player who has similar ratings to a starter, he might enjoy better results because the other 4 backup defenders aren't as talented as the other 4 starting defenders.

from what i have seen, the vast majority of players in HD will have improved offensive stats if they are moved from being a starter to begin a reserve.

to me, it is strictly a function of the fact that they will face weaker defenders when they come off the bench. okay, i guess thats not true every single game.... but i would bet you that in 80-90% of the games you play, the starter will be a better defnder than his replacement ( and when i say "better defender" i mean the whole package... he will be more athletic, quicker, and have better DE.

okay dukey, heres where you kinda lost me:

Even if the player has good matchups against the starters, there are certain guys who seem to perform better as bench players

yeah, he may have good matchups against the starters, but however good those matchups are.... they are going to be better against the subs. period. thats the whole thing in a nutshell.