Throwing in the towel has a negative connotation, but the truth is that not every fight can be won. There's no team with unlimited resources, and there comes a point when the near-term gains of staying in the race or even making a win-now acquisition is a far worse idea than simply living to fight another day.
When the Tigers traded Yoenis Cespedes away, they were only 3½ games behind the second wild-card spot. Does anyone really think the organization would be better off staying in a nine-team wild-card race back then rather than having Michael Fulmer in the rotation now? If last year's Yankees had decided to fight for a wild card, Clint Frazier and Gleyber Torres likely would be in different organizations right now.
We know the White Sox and A's and Phillies and Reds and Padres, and so on, are likely to trade any remaining veterans with value this deadline. Those towels have been in the ring for a month or more. But there are teams that still have realistic playoff hopes who should instead close the book on 2017.