KANSAS CITY, Mo. - The Royals and left-hander Mike Montgomery have agreed to a $3.1 million contract for next season to avoid salary arbitration. The club’s once-heralded prospect returned to Kansas City last season as part of a trade with the Cubs. He went 2-7 with a 4.64 ERA down the stretch. The numbers were good enough for the Royals to believe Montgomery could be part of the rotation next season. Montgomery made $2.44 million last season. He is 23-34 with a 3.83 ERA in 180 career appearances.