The 34-yearold Sunderland striker has been linked with a move to West Ham in recent days but Merson reckons Wenger should consider a swoop for the former England international.
On the Defoe link to West Ham, the former Arsenal man was quoted in his Daily Star column saying:
‘Jermain Defoe shouldn’t go to West Ham. But if I was Arsene Wenger I’d buy him for Arsenal.
‘I find it strange that West Ham want him. I think he’s a great player but they’re not going forward with him. He’s too old.
‘It’s different for Arsenal. Give him an 18-month contract and he can come on in games when they need a goal.
‘He’s a natural goalscorer and they don’t really have one of those. He’d get to play Champions League football as well.
‘Think how good he could be making those runs with Mesut Ozil and Alexis Sanchez supplying the passes.
‘He’d have the chance to win the league at Arsenal and he’d help them a lot. Next season he could get you 20 goals.’
However, Wenger has dismissed any transfer for a striker this month as he believes he has plenty of options in attack to see out the remainder of the season.
Defoe has been in fine goal-scoring form for David Moyes’ side so far this season, netting 11 goals in 20 Premier League appearances, but many would believe his best years are behind him.