Sam Thompson's Arm?

Questioning how in the new Hall of Fame set SOM released, he is a minus 5 in RF (and a 2e5 to boot). Those cards reflect an average of some of their prime seasons (i cant recall the exact range). How can the card in this game 1889 (+1) and 1894 (+2) show such a disparity in the arm?

Here is his BR link: http://www.baseball-reference.com/playe ... sa01.shtml

By the time he made the Hall of Fame set, steroids increased his arm strength and the -5 reflects that.

As an update, i checked the Hall of Fame Website bio of "Big Sam"
http://baseballhall.org/hof/thompson-sam

The blurb about him also reflects his "exceptionally strong arm"

Biography:
An outstanding slugger and run producer for the National League clubs in Detroit and Philadelphia in the Dead Ball Era, Sam Thompson was one of the most impressive batting stars of the 19th century. In addition to his 126 career home runs, the clutch-hitting Thompson also hit for average, collecting 200 or more hits three times and finishing his career with a lifetime mark of .331. He was also a fine fielder who was renowned for his exceptionally strong arm.

I use this guy all the time, he hits like a beast. If he was a 2e5 with a (-5) arm, he'd easily be a 10 million dollar player even with the lack of PA (and then i would never use him, lol)