"It's going to be an exciting season, there are a lot of games in the Championship", the midfielder told the club's official website.
Despite their season opener defeat to Wolves, Middlesbrough will look to perform impressively this term and return back to the Premier League as soon as possible.
"This opportunity arose and I thought it would be a great one for me".
"We'll see where that will get to within the coming days".
Antonio Conte watched Baker in pre-season after he returned from a successful two-year loan spell at Vitesse and allowed him to feature against Bayern Munich as they toured China and Singapore.
"I already know what the Championship is about".
Boss Garry Monk said Baker, 22, was on their shortlist to replace midfielder Marten de Roon, who was sold to Atalanta on Thursday.
Atalanta finished fourth in Serie A under Gian Piero Gasperini last season - above Inter Milan, AC Milan and Lazio - to qualify for the group stage of the UEFA Europa League. Baker is also a different option from any of Boro's existing central midfielders: Jonny Howson, Adam Forshaw, Adam Clayton and Adlene Guedioura.
The Championship is arguably the most competitive football league on the planet, and there is no better place for Baker to prepare for life in the Premier League.