The Hammers were strongly linked with a move for the Tottenham Hotspur striker on loan for the rest of the season on Monday.
However, the deal failed to materialise, and Thompson believes that missing out on Togo international Adebayor could prove to be costly for West Ham.
“West Ham’s big signing was to get Emmanuel Adebayor up front just to change things round, but they couldn't compete a deal,” the 61-year-old wrote on Skysports.com. “If they had got him in then Carlton Cole would have been allowed to go.
“That would have been a great signing for the Hammers, not because Adebayor needs to move on, despite losing his way at Spurs, but it would have given them another decent attacking option.”
Would Adebayor have been a good signing?
Adebayor has been struggling for form and goals throughout the season, and has managed just two goals in 11 Premier League appearances so far.
The former Arsenal star has created just 12 chances in those games, while winning 41% of the duels and a pass accuracy of 76%.
Based on current form, Adebayor would not have been a great signing, but the fact is that the former Manchester City striker tends to play well when he joins a club on loan.
Adebayor scored 17 goals in 33 Premier League appearances for Spurs during the loan spell in 2011-12 and five in 14 La Liga games for Real Madrid in 2011.