Wish I knew for sure. When looking at young birds in a change of plumage it can be hard to tell. Pic is just too fuzzy but he does seem to have a rather large head and it is white. Redtails heads are a bit more dark, round and this was a very large bird. Saw him again yesterday but further off. Will keep the camera close and try again. There is an established eagle community about 20 mile east of here :-/
It is funny just living outside Philadelphia, there is a nesting pair just inside the city limits and several nesting sites within a 1/2 hour drive. Saw one a few years ago carrying a squirrel over a residential area, and saw one while fishing in the Delaware river.
Not sure this is the same bird, head is much darker, looking again the pattern on back looks the same :-/ Must have been a RT > this one looks to be a juvenile red-tail hawk
Shot this pic with my phone thru a spotting scope at about 250-300 yards;