For the Hull KR forward – who spent four years with the Cheshire club – knows victory tonight over Salford Red Devils at the KC Lightstream Stadium would see the Robins use their game in hand to go level with the Wolves on 18 points from 19 matches.
Victory this evening would also see Hull KR leapfrog city rivals Hull FC to occupy the much-coveted eighth spot in the league.
Those positions could be reversed 24 hours later, as the Black and Whites play their re-arranged game against Wakefield Trinity Wildcats.
The thought of Tony Smith’s Warrington missing out on a top-eight place seems unlikely, but three defeats in their last four league outings – against St Helens, Huddersfield Giants and Hull KR – have given the two Hull clubs beneath them a glimmer of hope.
“We have a tough game against Salford, but if we can pick up a win there then we would be level on points with Warrington, with four games to go,” said McCarthy.
“It’s a good opportunity. As players you want to be playing, rather than training.
“You don’t want the tough running sessions and heavy weights – plus we are getting a few bodies back from injury, so that helps, and we can rotate a few positions.
“People are then playing for their places.”
The 27-year-old turned down a new deal at Warrington in 2013, frustrated with his lack of first-team chances – despite picking up two Challenge Cup winner’s medals.
Rejecting interest from Super League clubs, he took up an offer from former Wakefield centre Jason Demetriou at Northern Pride in Australia.
“I had a really good time at Warrington, but after 2012 I had a really frustrating season in 2013,” said McCarthy. “I probably wasn’t playing as much as I’d like to.
“At the back end of the season, the club offered me a new deal, but I just felt it was time for me to spread my wings and for me to kick on as a player.
“I spoke to a few Super League clubs, but it didn’t feel right, and an opportunity came in Australia to play in the Queensland competition out there.
“It was a good opportunity for me to start enjoying the game again, get back to a less-pressured kind of environment.
“Jason Demetriou, the former Wakefield player, was the head coach and he put a leap of faith in me and took me out there.
“It was a really good year, we had a strong team, and won everything we could do.
“My confidence had grown, from being a squad player at Warrington, and I then decided to come to Hull KR and return to a full-time environment and try to kick my career on.”
His time in Australia has certainly helped McCarthy hone his skills, and Hull KR are reaping the rewards this season.
“Because of the competition at Warrington, that’s probably what I struggled with,” admitted McCarthy, who also had a loan spell at Wakefield in 2011.
“If I had a bad game I got dropped, which is understandable, as that’s where they are for competition for places.
“Going out to Australia, allowed me the opportunity to work on things every week and allowed my game to progress.
“That’s carried on at Hull KR, with Chris (Chester) having a lot of faith in me, to start me at the beginning of the year.
“I am just having a lot more relaxed approach to the whole game, rather than being so intense about form.
“My game is a fairly simple one, you can teach most lads to do it.
“My game is focused on hard work, and being as honest as possible – tackling when I need to, and taking carries when I need to.
“I am not going to make 100m tries from anywhere, but if I keep doing my job – and my team-mates and coach are happy – then I am more than happy to do that for anyone.”
Confidence is high at Hull KR, having reached the semi-finals of the Ladbrokes Challenge Cup, and picking up back-to-back Super League wins over Widnes and Warrington.
Tonight completes a remarkable home run for the Robins, their fifth consecutive match at Craven Park in the month of Junes.