Sentence:  At one time or another every Springfield player was designated a "<WSD>black ace</WSD>."  According to Kilrea, that meant reporting to the rink at 8:30 in the morning and skating from 9 to 11. Another session followed in the afternoon, from 12 to 2, and Shore would keep his ace, or aces, out on the ice sometimes until 4 P.M. All in the name of discipline. 
Meaning of the word marked with <WSD> tags:  A player from a junior league who is called up by an NHL team after their original team's season has ended and kept as a reserve player.