Alexis Sanchez may be out of the game but Walcott is not a bad alternative to have.
The Englishman relies on his pace and ability to terrorise the defenders down the flanks and can cut inside as well.
Boro will have to make sure that their midfielders do their jobs when it comes to marshalling Walcott and their wide men will need to track back and help their fullbacks limit the crosses Walcott can put into the box or shots on target he has.