I believe Roark can and will bounce back and give us 180+ solid innings. He's 32, so not "over the hill." He's been healthy. He was great in 2014 (2.85 ERA), had a rough 2015 bouncing back and forth from the bullpen, then was great again in 2016 (2.83 ERA). Granted, he now has had 2 sub-par years in a row, but I just think he'll figure it out. He's a competitor, and he's going to want to secure a decent free agent deal that takes him to the close of his career. Motivation can be a powerful thing.
I'd be interested in some theories as to why he tailed off so much in 2017 and 2018.