Failed to tag first
Runner on 3rd; batter hits what appears to be a double and the runner scores. Umpire then calls the hitter on 2nd out because he failed to touch first. (Cleveland and Chicago this last Saturday.)
According to the comment on MLB Rule 10.10(a)(1):
"If a putout results from an appeal play within the natural course of play, the official scorer shall give assists to each fielder, except the fielder making the putout, whose action led to the putout. If a putout results from an appeal play initiated by the pitcher throwing to a fielder after the previous play has ended, the official scorer shall credit the pitcher, and only the pitcher, with an assist."
I didn't see the game on Saturday but it sounds like the appeal was probably initiated by the pitcher, with the first baseman covering first, so score it:
13/G.3-H (or /L if it was a line drive)
A similar situation occurred last year (2009) in a Braves-Cardinals game on July 29: Joe Thurston hit what appeared to be a double but was out on appeal for missing 1B. The Retrosheet event logs score it thusly:
so I'd be pretty confident with this scoring.