The 21-year-old, who was snapped up on a temporary basis from Southampton last June, has enjoyed an outstanding year at the Banks’s Stadium.
McCarthy played every minute of every game for Jon Whitney’s side – a feat he also achieved during a loan spell at Wycombe in the 2015/16 campaign.
His performances were rewarded on Sunday when Walsall supporters crowned him their player of the season.
And the defender said he is hugely grateful for the backing they have given him over the past 12 months.
“I can’t thank the fans enough – they have been amazing,” McCarthy said.
“I’ve got so many people to thank but the fans have given me so much energy.
“A lot of people have talked about my energy and how much I run in a game but it’s the fans that give me that.
“And I can’t thank them enough for giving me the player of the season award and for roaring me on every week. They have really made me feel welcome. I have taken to the club and I feel a big part of it.”
McCarthy believes he is a different player now to the one that initially joined the club.
“It has been a great learning curve for me and I feel twice the player now to the one that joined,” he continued.
“I am a completely different player and I feel so much better for the experience.
“I can’t speak highly enough of the club. The chairman, the manager, all the staff. They have all been brilliant with me.
“The players have also been great. I’m someone who likes to listen and learn and absorb everything. I’ve come a long way. I’m grateful for everything the club has done for me.”
Despite his outstanding season, McCarthy – who is out of contract next month – is yet to be offered a new deal by Southampton.
And while a host of clubs are believed to be keen on securing his services – the defender won’t rule out a return to the Banks’s.
“I am out of contract at Southampton – there is nothing there that I am aware of so I have got to keep my options open,” McCarthy said. “I will sit down with my people in the next couple of weeks and see where to go from there.
“Coming back is an option, of course it is. The manager has been so good with me and I have to bear that in mind.
“Walsall will be higher next season, believe me. They will be pushing so there are lots of things I have to consider.
“But I am very ambitious as well. I want to get to the top as quickly as possible.
“I’m ambitious but I am realistic and I know my next move has to be right for my career. I’m not looking too far ahead but I know I have to make the right next step to help me develop again.”
McCarthy added he is particularly proud that he played every minute of every game last season.
“I’m very proud to have played every minute,” he said. “Some of the boys like Jimmy (O’Connor) say they haven’t done anything like that. I’m very proud of it and it will live with me for a long time.
“It’s a crazy stat and I have felt every emotion. I managed to do it last year at Wycombe as well so, touch wood, I can keep going.”