Integrating running with lifting

I’m going to start adding sprinting to my 15yo nephew’s football training and I’m looking for advice. My thought was to start off by going to a track and sprinting 100’s and walking the turns for a total of 10-100’s. I would have him work in the 60-80% range. I had figured on doing this a couple of times per week for about 3 weeks just to start to get him conditioned (he is 10 weeks out of pin removal from a liz franc fracture in his left foot).
Once conditioned I intend on having him do more work in a shorter distance range but I’m not settled on any specifics. I’m kind of at a loss as to the best way to incorporate his running with his lifting.

I prefer to run in the mornings and lift in the evenings. I would just make sure the running is done before the lifting or do the running on days he doesnt lift at all.