The 35-year-old striker was named as Micky Adams' number two at Vale Park on Tuesday, but he will combine his position with a playing role and is likely to spearhead the Valiants' attack going into the new campaign.
"The manager has brought me in to help the strikers, work with the team and do some scouting. I believe I have the ability to pass my knowledge on, but I also want to play as many games as I can and get this club promoted," Horsfield, who recently made a full recovery from testicular cancer, told the Sentinel.
"It is going to be hard because we have a young squad and not many signings. But hopefully the work we will do on the training ground will come to fruition."
Adams, who was appointed as Vale boss earlier this summer, added:
"He fits all the criteria I was looking for.
"He wants to coach and is taking his badges, but he also still has a little bit of life left in him as a player. He has always been a handful for defenders. They know that when he's playing they are in for a tough afternoon."