I think Day has played the portal beautifully so far. He certainly hasn't overly relied on it, but the 3 main guys they've brought in the last couple of years - Fields, Jonah Jackson, and Sermon - have been huge (Jackson last year, Fields was and will continue to be, and Sermon is certainly a proven entity from his Oklahoma days).
His recruiting is kicking so much ass that he doesn't really need to rely on the portal much. There will always be situations that occur that can be cured by the portal, though. Particularly, the RB situation this year and the QB situation last year.