The Seattle Mariners, looking to end a postseason drought that stretches to 2001, acquired the best arm on the trade market Friday night in a deal for right-hander Luis Castillo of the Cincinnati Reds.

Minor leaguers Noelvi Marte, Levi Stoudt, Edwin Arroyo and Andrew Moore are headed to Cincinnati, the teams announced. Marte, a shortstop, is the highest rated of the group, with ESPN's Kiley McDaniel ranking him the 12th-best prospect in baseball ahead of the season.

"We felt this was the best return we could get for Luis,'' Reds general manager Nick Krall said.