I'm not sure if it's a pajama top or a thick undershirt, but it seems like either would be fine. If it's a little chilly, I think a short-sleeved undershirt and this will be no problem. This is just my personal opinion, so please keep that in mind. There is some wear and tear, but it's still wearable. Please note that it may be compressed for shipping. Please purchase only if you understand that this is a used item and has been stored at home. Since this is a personal inspection, there may be overlooked stains or other imperfections. Please refrain from purchasing if you are concerned about this. In some cases, the shipping method may be changed from Rakuraku Mercari Bin to Yuuyu Mercari Bin. I will be listing more children's clothes, men's, and women's items, so please check them out! ※ Please see my profile for other information.