After ranking second on the Best Defensive Outfielders list, Krizan claims the top spot among outfield arms in the system. His arm fits well in right field and he has enough strength to make base runners think twice about taking an extra bag. His grades are consistently plus from scouts and some will stretch a little further if they've seen some of his best throws. Connor Harrell's arm comes up just short of Krizan's because he lacks the consistency of Krizan.
Moya's arm strength began to come back this season as he continued to distance himself from Tommy John surgery that cost him a large chunk of the 2012 season. While he still wasn't all the way back, Moya unleashed the occasional plus throw, and frequently showed off an above-average arm that fits his right field profile.
Both Tyler Gibson and Jake Stewart show consistently above-average arms from the outfield. Gibson's arm has taken a step forward since high school as he has adapted to outfield throwing mechanics after playing shortstop as a prep standout. Stewart's arm has shown better in the past, but scouts were less impressed in 2013.
Ben Guez was very close to making this list and an easy argument can be made that he has earned one of the latter spots. He frequently shows an above-average arm that plays at any outfield position, and his accuracy has improved throughout his minor league career.
Both Miguel Paulino and Ben Verlander could sneak onto this list next year. Paulino offers impressive raw arm strength but remains wildly inconsistent on the diamond. Verlander's arm strength is still coming along as he adjusts to playing every day. He showed impressive arm strength on the mound in college and he just needs that to translate to the outfield.
The Tigers have long believed that Ariel Serrano could improve his arm strength and show off a true plus arm from the outfield. He began to show that type of arm strength a little more frequently in 2013, but still has a ways to go. Valdez has the classic right field profile that includes a strong arm, but his accuracy and long release must be improved for his arm strength to be a weapon in the field.