The 25-year-old defender, who was released by financially crippled Bury, has held talks with Horton and looks set to sign for the club within the next few days.
Collins, who impressed Horton in The Shakers last match of the season, made over 80 appearances during his three-year stint after the club after joining from Huddersfield Town.
"We've held talks with Sam (Collins) and his agent today," confirmed Horton to port-vale.co.uk. "They've been good talk so hopefully there's a pretty good chance he will come here.
"I've had him before as a player at Huddersfield, he's played a lot of First Division football for his age and I'm very hopeful that he'll come. I'm very, very confident that he will join us.
"He's a big centre-back, he can throw it a mile. I signed him on a good contract at Huddersfield because I thought he could get to the top, and I still think he's got the ability to go to the top.
"He's got good feet, he's good in the air obviously as he's six foot two, and he's very strong. I think that him and Walshy, no matter what system I play, they'll be a very, very strong two.
"We've had good talks with the chairman and hopefully he will join us on 1st July. He's got to talk to his family before he comes to a decision, but I'm quite confident he will come".
Collins himself was pleased working for Horton whilst the pair were at The Terriers, but has not yet decided whether to sign or not.
"I've played for Brian before at Huddersfield and I really enjoyed working with him there, I did really well for him, so if things go well and I decide to sign it'll carry on how it was then," said Collins following the talks.
"In the past two or three years I feel I have grown up as a footballer. Working with Brian again will just bring everything back out in me like it did before when he had me at Huddersfield. I think I will become an even better footballer.
"There are other clubs interested, but I've got a wife and two young children, so there's a lot to think about. It's a worrying time so I've got to talk to my wife and I've got a lot to decide, but with Brian Horton being here it will have a bearing.
"I played for him before for three seasons and was always impressed with him, and I've played against his teams in the mean time and have always been impressed with his teams, so if things go well, hopefully we can get things sorted".
