I had a guy miss an entire week, after getting around 30 minutes the week before, then just like 46 or something again...he went to 8.
This doesn't surprise me.
I consider that BBers are generally too bold with high minutes and too unadventurous with low minutes.
Terrible cases of Gs are rare so it's difficult to draw conclusions but by experience, i find it's better to start slow after an injury and at the start of the season. Plus even if it is unconfirmed, I have seen too many occurences of players hit again by an injury just after a recovery and I don't like to start good players immediately.
I have tested it two times with long-term injured players. One time with a player I bought with pitiful GS, he upped to strong in 3 weeks by playing "only" 37, 56, 55 minutes in that order. I can show you the player and the weeks but you'll have to take my word for the Gs levels.
What is usually taken as optimal by the tips of the forums is higher than what I find optimal myself.