Honus Wagner, circa 1911, which is available in a 55MB digitized file from the Library of Congress. It is a pleasure to see institutions provide such high quality copies, yet with material of this age the odds are pretty good that someone has been sloppy about handling the document. In this instance the biggest problem is a fingerprint beside the right elbow.
Whenever a restoration task seems daunting a good approach is to do the easiest part first. A little time and familiarity makes it simpler to work out the rest. So we'll start at far right. I used the Photoshop healing brush tool at 100% hardness and 9 pixels. An important trick to getting good results is to change the source sampling point frequently.
Editors who are more ambitious could try what I did here: it is possible to use the healing brush effectively at borders if the source area and destination area are close matches. I reset the tool diameter to 5 pixels and sampled from a border section lower on the leg, then applied the tool to the fingerprint marks at the edge of the bright area. The advantage of this approach is that when it works it yields a very good blend. If the results aren't desirable at the first attempt, just back out through the history and start again.
Although the clone stamp tool is good for restoration at low hardness, I nearly always keep the healing brush set to 100% hardness. Anything less gives muddy results. Here's how the area appears after a few minutes' work.
Fingerprints are chemically interesting. From a preservation standpoint that means there's a strong likelihood that oils and dirt will cause chemical reactions on a photographic print. Those changes can't be brushed or washed away. Attempts at cleaning often cause additional damage. When you need to scan a damaged print, might as well leave bad enough alone on the physical item and correct the problem digitally.
So if you have a family member with bad habits at handling old prints, sit them down and show them this post. Better yet, fire up an image editing program and task them with cleaning up their own mess. Whether the goal is to preserve baseball history or family memories, it's much less effort to wash one's hands and hold photographic prints by the edges.