Saturday's spring game will preview a completely different Ohio State team from a year ago. After a roster overhaul that saw the loss of 12 starters – including potential top-10 picks Caleb Downs, Sonny Styles, and Arvell Reese – the Buckeyes enter this spring game with many questions on who will replace these stars. Here are three key position battles to watch during the game. Linebacker It is never an easy task to replace a first-rounder at linebacker, let alone two. Styles and Reese fronted one of the elite linebacker pairings in the country last year, contributing 151 tackles and 7.5 sacks for the top scoring defense in the country.  Payton Pierce is expected to start at one of the linebacker openings, after appearing in all 14 games and recording 44 tackles last season.  The other spot is a battle between 4-star Riley Pettijohn and Wisconsin transfer Christian Alliegro, who has produced 119 tackles the last two years as a Badger.…