Complex sentence: They are usually employed in a 3-5-2 formation, and could therefore be considered part of the midfield, although they may also be used in a 5--3--2 formation, in which they would have a more defensive role.
Split into simpler sentences: They are usually employed in a 3-5-2 formation, and could therefore be considered part of the midfield. But they may also be used in a 5-3-2 formation and therefore have a more defensive role.