Is there a ratings bump on prospects after the season ends and when the rollover happens? I have two pitching prospects that are not ML ready yet, but I'm trying to decide whether to extend to veteran contracts for one year. I'm also guessing if there is a ratings bump, I won't know how much it is before I have to decide on extensions, right?

All the physical ratings get adjusted at rollover. Typically, increases for the younger players, decreases for the older ones.

By physical ratings, I'm taking about durability, stamina, speed, power, range, arm strength, and a few others.

DUR, STA, and VEL are the only relevant pitcher attributes that increase in offseason, so if they aren't ready yet, chances are they still won't be come the start of next season.

Like tec said, info is available at rollover, so yes you can see this info into account before making a decision.

I finally just now realized the benefit of keeping players in the minors as long as possible. I had a closer in AA pitch all the time because he was the best reliever so he got a ton of playing time. I promote him to the majors because he is an upgrade to who he replaced but he now is basically a setup B and has pitched 4 innings in like 30 games.