Wednesday afternoon, the red-hot Athletics won again, this time beating the the Royals on Mark Canha's 11th inning walk-off double (OAK 1, KC 0). It was Oakland's 13th win in their last 16 games and their 55th win in 80 games since June 17.

Despite the win, Wednesday brought bad news for the A's. Setup man Blake Treinen is done for the season with a back injury, manager Bob Melvin revealed following the win. Treinen provided more details:

Treinen last pitched last Friday, when he allowed two runs in one inning against the Angels. He's pitched to a 4.91 ERA in 58 2/3 innings this season, a far cry from last year's All-Star performance (0.78 ERA), but he had been much better of later. Eight of his last 11 appearances were scoreless.

Melvin removed Treinen from the closer's role earlier this year -- Liam Hendriks has been lights out in the ninth inning -- but he remained an important part of the bullpen thanks to his experience and ground ball ability. With Treinen out, the A's bullpen hierarchy shakes out like so:

Luzardo and Puk are two of the best pitching prospects in baseball and they could see an increased workload down the stretch with Treinen sidelined. Luzardo in particular has been electric this month.

Wednesday's win improved the Athletics to 91-61 season. They sit in the top wild-card spot and have a 2 1/2-game lead over the Rays. Oakland is three games up on a postseason spot in general.