Clark, 30, made his first league start of the season in the 1-0 win against Manchester United last month and in the four games following, the Magpies have won twice and had one draw.
The former Aston Villa defender is back in the Ireland squad for this international break and McCarthy has revealed that he has always been someone he has wanted to call-up amid his injury problems.
“I watched him at West Ham, I thought Newcastle were brilliant to be quite honest,” said McCarthy, as quoted by the Northern Echo. “He has scored a couple of goals, but he is not somebody I need to watch. He is not like a new player we have suddenly found.
“I know Ciaran, he was in my first squad. It (the fact he has not been selected recently) is just the fact that he has been injured. Now, he has been playing, and Newcastle have had some good results. Maybe that is partly down to him as well.”
Clark has been immense for Newcastle in the last month. His return to the starting line-up coincides exactly with when Newcastle’s form started to improve and although it was would be simplistic to say it’s solely down to Clark, he’s certainly made an impact. The Ireland defender has played superbly in the back-three and has even scored in two matches on the bounce in wins against West Ham and Bournemouth. He’s joint-top goalscorer for the Magpies, although that says more about the poor fortunes of the attacking players rather than Clark’s instincts inside the penalty box. Hopefully Clark does not suffer any kind of setback during his international duty for Ireland. The last thing that Newcastle need right now is yet another defensive injury with doubts surrounding Jamaal Lascelles after he went off early in the win against Bournemouth at the weekend. Newcastle’s defence has been brilliant and changes can upset their form.