Tackles (Team/Selected Player) -\n\n "A tackle is defined as when a player connects with the ball in a legal, ground level challenge and successfully takes the ball away from the opposition player. The tackled player must be in controlled possession of the ball to be tackled by an opposition player. "

They're are actually three types of tackles - to of which are counted under the "Tackle" column. In other words, Tackles does not equal Unassisted Tackles. It is the "Assisted Tackle" that gets lumped in the with "Solo Tackle." Assisted Tackle and Tackle Assist occur on the same play.