This is interesting.
I'm using the MVP 2013 Mod (meaning that, unless you fix the calendar, you have a lot of 11-year-old players playing) and just progressed through my first season in owner mode and got through player progression. I noticed very little correlation between the Career Potential Star Rating on the 'Edit Player' page and actual progression. In fact, almost all of the 12-year-old prospects (19 in 2013 age) regressed slightly, regardless of their Career Potential rating. Well, that shouldn't be happening.
Given that the game, under factory settings, would not have had 12-year-olds playing, I decided to tinker around with his age, using a 12-year-old 5-Star shortstop (Elpidio Cox, one of those fictional players sitting around in the free agent pool at the beginning of year 1 whom I signed) as a control. Since age is a factor in player progression, most obviously in players' 30s and 40s, when they're declining, I wondered whether the extreme youth of 13-year-old prospects was also a cause of decline.
My method of testing is totally unscientific and inconclusive, but what I did was save *just* before player progression, edit his birth year (hence, his age), and run the player progression for that age. I repeat this six times by quitting and reloading the save point to minimize (but not eliminate, granted) the randomness. I ran ages 12-19, stopping at 19 because I assume that once a player reaches 20, things start working as expected.
Each run, I recorded and totaled the change in vLHP Power, vLHP Contact, vRHP Power, vRHP Contact, and Speed. The data is in an attached .rtf file. Below are the summaries of each age's total points gained or lost, listing mean and median of each age's six runs.
Age 12:
Mean: -2.16
Median: -2.5
Age 13:
Mean: 8.3
Median: 9
Age 14:
Mean: 29.3
Median: 29
Age 15:
Mean: -8.16
Median: -10.5
Age 16:
Mean: 6.3
Median: 3
Age 17:
Mean: 0.83
Median: 2
Age 18:
Mean: 38.3
Median: 37.5
Age 19:
Mean: 32.6
Median: 31.5
I figure that 18-and-older is normal gameplay. 16-and-17-year-old players exist in real life, of course - mostly International Signings - but it seems that the game keeps their improvement near zero until they hit 18 - if I were to guess, to prevent the super youngsters and fictional signings from taking over the game.
But the most striking thing about this is the massive weirdness that occurs at ages 12, 13, 14, and 15. I have absolutely no idea how that works. I don't actually expect an answer, of course (though if someone's familiar with the coding of the progress files, I'd listen). I don't think I'm wrong, however, to say that this makes year updating *really* important for realistic gameplay - not just 'haha Pujols is still improving !!' but to actually ensure that prospects are entering the majors at a reasonable rate.
If you did look at the data .rtf, the randomness can be huge. So if you *do* want to re-roll to get a 'good' draw for your favorite player, be sure that you know what a 'good' draw is. Sometimes a net gain of one can be a huge dice roll in your favor, and sometimes a net gain of 30 might be a bad roll.
tl;dr: Year Updater + RNG!!1!one!
Addendum: I don't know if this post will be useful or interesting to anyone here, of course. If the mods decide it contributes too little for its size, feel free to delete.
Hail The Glorious RNG.rtf
