Blue Jays right-hander Marco Estrada is pitching despite a herniated disk in his back, tweets Jon Morosi.

Estrada, 32, has pitched to a 3.78 ERA (114 ERA+) and 2.52 K/BB ratio this season. Estrada boasted a 2.93 ERA at the break, but in 10 starts since then he's run an ERA of 5.47. Those recent struggles are likely related to his ongoing back problems. On Wednesday, Estrada took the loss against the Rays, as he allowed four runs in 5 1/3 innings. Over his last six starts, he's got an ERA of 7.53. In related matters, Estrada has also experienced some troubling recent trends with his velocity and spin rate.

Estrada opened the season on the disabled list with back soreness and later missed much of July because another back-related DL stint.

The Blue Jays are of course in the thick of a tight American League playoff race, and they already have rotation concerns, what with the workload concerns and blister problems of Aaron Sanchez.