Havertz made a £65million summer move from Chelsea and is yet to show his best form for the Gunners, with just one goal, a penalty against Bournemouth, and an assist across the 18 matches he has played in all competitions.
The 24-year-old was regularly used as a striker at Chelsea but has primarily featured in midfield in an Arsenal shirt, at times on the left of a midfield three and in recent weeks on the right in the absence of captain Martin Odegaard.
Mikel Arteta said ahead of his side's win over Burnley, in which Havertz was replaced on the hour mark, that he was "really pleased" with the German, but admitted that he needed to "improve" in front of goal.
Havertz has not been used as a striker even when Gabriel Jesus and Eddie Nketiah have been out injured for Arsenal, a decision that Merson believes has been a mistake.
"He’s struggling a bit," Merson told Sky Sports. "He had a shot that got blocked, if you’ve got four in four you hit that and it gets deflected or you hit it sweetly and it goes in.
"I feel sorry for him, I don’t think he’s a midfield player I think he’s a centre forward. He’s 6ft 4in, maybe he’s a No.10. What he did do and they did well Arsenal they got the ball in the box and he got in the box.
"He’s a big lad I hope he does well I think he’s a special player and he’s struggling. Everyone struggles in their career and he’s having that moment and the moment and hopefully he gets through it."