A simple answer is not possible from the information you have given, but the bearing manufacturers want you to succeed, so everything you need has been published.
It's in the 'engineering' section of the thicker bearing catalogs, and probably somewhere in their websites.
I have a frame 364TCV G.E. electric motor and it has wear of material in the area of the bearing on the side seat attach. Wear is 0.018 "with respect to the unused side of the engine which is 2.756" what welding procedure should apply not to damage the winding of the motor.
Sleeving usually works well on an ID, but not so much on an OD (thin cylinder in compression seems to do much better than thin cyclinder in tension).
There are a variety of processes for shaft buildup.
* Welding has the potential to warp the shaft. It is highly dependent on the skill of the person doing the job and perhaps some stress relieving.
* Flame spray
* Metallizing
* Epoxy
Most require to machine down the shaft first so you can build up a thickness exceeding the minimum, then another machining to final dimensions.
I'm not sure one process is necessarily better than another but it is important that the people doing the job are familiar with the process. I wouldn't do it myself if you have to ask these questions. I would find a reputable shop to do the job and ask them what process they propose to use and how confident they would be in the repair.