As one who shares Mark Goodson's indifference to sports, I applaud his courage in emerging from that particular closet (''Lousy at Sports,'' About Men, May 11). In my case, this unmanly tendency came close to having serious, and possibly fatal, consequences.

It was during the Battle of the Bulge, in World War II, when there were reports that German troops, wearing American uniforms and speaking idiomatic American English, had infiltrated near where I was serving as a sergeant attached to Seventh Army Group Headquarters in Vittel, France. The word was that soldiers suspected of being Germans in disguise were being asked such questions as ''Who plays third base for the Detroit Tigers?'' and that those unable to answer correctly were immediately put to the sword.

No German in disguise could have been more completely stumped by this question than I would have been. I was fortunate enough not to have aroused anybody's suspicions during that particular time. I can only hope no luckless G.I. who shared my ignorance of such matters had to answer that kind of a question or that, at least, he was somehow otherwise able to satisfy his inquisitors that, even though he knew nothing of professional baseball, he was still not deserving of immediate execution. GERALD LANK New Rochelle, N.Y.