This peach tree looks incredibly healthy for being dug up and potted. Seriously! That graft or injury is just fine. Obviously because the top growth isn't even wilted! Your tree looks very healthy. It would not if there were any problems with this injury, from staking or graft? This looks just fine. Keep it watered. How long until it gets its new home? I'd give it a little balanced fertilizer. Leave it alone except for regular watering, 2 X a week soaked?
When did you dig it up? I'd love to hear that part of the story and so would others. Did you do this last winter...for you...or during the growth season? Is this potting soil or the soil it was already in? (one of the rare exceptions for not using potting soil). Depends on how long before you'll be able to transplant it into a forever home...
As far as I am concerned this tree removal was a success! You should definitely aim for your fall/winter to transplant again. No later. Mycorrhizae addition when transplanting. Excellent health for a newly potted tree from the garden...did this tree have staking?