Night Owl Cards

I received this card from deal in the big '55 Topps Jackie Robinson transaction a couple months ago. I didn't want to display it until I figured out the mystery of the "front line 5" written underneath Westrum's position and team. But I give up. I'm stumped. Obviously, it doesn't have to do with his position, as "5" is the number designated for the third baseman. It doesn't have anything to do with his uniform number because baseball-reference says he wore Nos. 40, 6 and 9 during his career. And the "front line" mention has me puzzled, too. That is terminology best used for football or hockey or even volleyball. The other thing that confuses me is the writing appears to be that of an adult, not a kid. What adult writes on a 1956 card? Here is the back. If you can get past the tremendous cartoon on the left-hand side, you'll note that there is another random number on the back -- "37." What does that mean?...