I was just wondering if you change a rookie's position before training camp. Does it effect the boom or bust?

No it’s a separate roll

Additionally:
....sometimes a bust can be leveled off by switching positions AFTER TC, particularly from wr to rb...
Or, LB to dline.
I've found I have to be honest about player positions though, and actually SWITCH the players position. I cannot keep a WR failure as a WR, use as a RB, and expect success.
I've found I must change that WR to a RB, that LB to a DE, or the benefits are short lived and the collapse is sudden.

It's contrary to the current "lighter than" thinking being the best method in the offensive backfield (though using a straight WR in the backfield for weight reasons only is definitely a broken aspect. ...and still used in the NFL so no arguments here).

However, if I recall right as it's info I gathered from reading these very forums, once an attribute begins to decrease, it will never increase. They only lessen their depreciation for a few years or (more likely) continue to decrease exponentially.

As a suggestion, many MFN gamers track attributes of players drafted via notes, pics, etc depending on their access medium. ANother awesome tidbit I learned from reading these forums. Find your path and good luck :)