Hole in Aspen Tree
I am not sure where you are located but aspens can be difficult to keep healthy in certain areas in Colorado such as the Front Range. Aspen prefers the moist but well-drained, slightly acidic soil found at higher elevations. At first glance, it looks like there is some past damage to the tree and that is why it is sappy. Although this may stress the tree a bit, it should recover and heal on it's on just fine. Having said that, The thin bark of aspen is damaged and injured easily, which can allow pathogens and certain insects easy entry. Fungal diseases, such as Cytospora or other cankers that attack the trunk, are common, as are diseases of the foliage such as rusts or leafspots. Of these, your photos look most like Cytospora. Of the many insects that attack urban plantings of aspen, oystershell scale, aphids and aspen twiggall fly are most prevalent. Spraying aspen foliage to control leaf diseases or insects often results in injury to the foliage (phytotoxicity). Aspens are notoriously prone to phytotoxicity from insecticides or fungicides. So, there is not a whole lot that can be done once one of these pests is established. Here is a link to descriptions of these common ailments https://csfs.colostate.edu/forest-management/common-forest-insects-diseases/common-insects-diseases-of-aspen/#1464022830645-f146fb5b-a5b6. Overall, both physical damage and Cytospora will not kill the tree, so I expect this tree will recover just fine. However, I would notify whoever you purchased the tree from that it arrived damaged.
Thank you so much!