June 21 was the day MLB started going after the sticky stuff.
Barnes pre-June 21: 29.1 ip, 16 h, 10 r, 10 er, 7 bb, 52 k, 3.07 era, 0.78 whip, 16.0 k/9, 0.55 h/ip, 0.23 bb/ip, 70% strikes
Barnes since then: 16.0 ip, 10 h, 6 r, 4 er, 5 bb, 18 k, 2.25 era, 0.94 whip, 10.1 k/9, 0.63 h/ip, 0.31 bb/ip, 65% strikes
So he's had a better ERA, but has allowed more baserunners, and he's struck out guys at a lower rate.
I mean, until the very small sample Toronto series, from June 21 til before this weekend's series, he had put up this line:
14.2 ip, 8 h, 3 r, 1 er, 4 bb, 16 k, 0.61 era, 0.82 whip, 9.8 k/9, 0.55 h/ip, 0.27 bb/ip, 65% strikes
So it doesn't appear to be the sticky stuff issue. He had a bad couple of moments this weekend.