QPR loanee Tom Carroll wants to "make it at Tottenham" but is prepared to consider all of his options at the end of the season.
Ilkay Gundogan has commited his future to Borussia Dortmund by signing a new contract.
The 24-year-old Malian international was linked by the French media with a switch across the Channel - with Boro said to be keen.
"I am flattered by the interest of a good club like Middlesbrough," Sow told Sky Sports.
"I just want to finish the season strongly and we will see, but I will take an opportunity to join the English League even if it is not the Premier League. I think the Championship is also the best second league in the world."
Boro boss Tony Mowbray was in Europe over the weekend watching potential new players, and he was believed to have watched Segunda Liga leaders Elche take on Girona on Sunday, with Paraguayan striker Javier Acuna reportedly one target from that encounter.
And Mowbray admits he is looking far and wide for new targets, saying of his travels: "It's part of the job. I'm following up what our scouts do every weekend.
"They compile their reports, I read their reports and if they like the look of this lad so I'm going to take a look at him and verify if I like him.
"Bottom line, if I don't like what I see then I won't be signing him, that's the way a scouting system works.
"You have to see if the potential signing fits into how you want to do things moving forward."
Mowbray insists he wants his business doing sooner rather than later, adding: "The plan is always to get the business done as soon as you can.
"It's very, very difficult to do that of course because clubs want the biggest fee possible for their player, unless they are out of contract, of course.
"With free transfers, you negotiate with their agents, bring them over, let them have a look around and see whether we can do a deal.
"But in transfers with money involved, clubs like to leak it out that so and so is available and so and so is looking at them, creating more interest and upping the price, it drags on and drags on.
"If we can do business we will try to of course."