Others have talked about how he bounced back over the second half, but if you just look at 9/1 to the end of the season, he put up .220 .298 .321, with 41 Ks and 12BBs in 126 PAs.
Well, 9/1 to the end of the season isn't the "second half" though....from July 20th to August 31st, which is a quarter of a season, Desmond hit .312/.378/.574 with 2 errors and a .986 fielding percentage. Obviously at other times he'll be extremely cold due to the strikeouts when his BABIP is low.
Anyways, I don't think Desmond is a world saver, but it is accurate that he can "carry a team for periods" in my opinion. He did it last year for 6 weeks during the worst season of his career.