Originally Posted by TakerNGN74
You can turn any wrestler instantly upon signing them without having to run an angle to do so. Not sure if it works with call ups but I don't see a reason why it shouldn't.
You can sometimes run into an issue if the wrestler has been called up once before like if you wanted to see him in a dark match or something similar.
If you called him up and then wanted to change their disposition, the game might penalize you for doing a change with no build up, or it hasn't been long enough since their last shift.
I've seen the 2nd one a few times as I used to bring up people from development after the Supreme Challenge like the WWE would do after Wrestlemania. But I'd have them in dark matches on B shows or something to see which ones that I wanted to bring up.