Detroit Lions training camp centers on Terrion Arnold and Isaac TeSlaa, two youngsters poised to reshape the roster. Arnold, a second-year corner, has caught coaching and teammate eye for steady progress. TeSlaa, a rookie, looks the part of No. 3 receiver as Detroit reshuffles depth after trading Tim Patrick to Jacksonville. Penei Sewell lauds TeSlaa’s physicality, while Arnold notes his blended quiet-off-field, ferocious-on-field persona. Green Bay looms Week 1, and TeSlaa’s rise could alter early target shares.