After the American Association folded following the season, Brouthers was sent to the Brooklyn Grooms of the NL, where he played two seasons. Most of his success came in that first season, when he led the league in batting average, hits, RBIs and total bases. For the season, he played in only 77 of the team's games, but did well, hitting .337. After the season, Brouthers was traded along with Willie Keeler to the Baltimore Orioles for Billy Shindle and George Treadway.