The former manager suggested over the weekend that the deal to bring the £12.7m man to Teesside was not made by him.
Alves moved to the Riverside in January 2008, for a club record transfer when he signed from Dutch side Heerenveen.
However, the striker failed to live up to his price tag and was sold in summer 2009, scoring just ten goals in 41 appearances but Lamb insists Southgate was fully behind the transfer.
I'm personally surprised and disappointed not only with the timing of Gareth's announcement but that he has chosen to make these comments at all, Lamb said.
Gareth has publicly confirmed his involvement in signing Alves on more than one previous occasion and that was absolutely accurate.
The truth is that in the 25 years I have been with the club no player has been signed without the full agreement of both the manager and the chairman.
The manager has always had the final say on potential signings because it is his team and that was very much the case with Alves.
Ultimately, it didn't work out for Alves at Middlesbrough and we had to move him on due to the financial implications of relegation from the Premier League, but we all felt at the time that the player had an excellent pedigree and would score goals in the Premier League.
Source: Northern Echo
Source: Northern Echo