Cobb, who came up through the Rays' organization, is expected to sign elsewhere as a newly minted free agent this offseason.
"First thought is it's unfortunate, because it means we're completely eliminated from it, and you'd really enjoy having one more start that meant a lot and kept us in it," Cobb said. "But the math didn't work out for us. Then I guess you start thinking about your career.
"This chapter could possibly come to an end. You know, I don't ever rule out anything in this game for the things that I've seen happen. Seem to hear more in the media that I'm not coming back than I've thought about. If that is where this road leads us, it's sad to think about."
Cobb has been a special pitcher for the Rays, albeit an oft-injured one. Of note, he got hit in the head by a line drive and returned. And he had Tommy John surgery, and also returned.
The Rays not starting Cobb in a game after the team had been eliminated spoke volumes to the right-hander.
"I'm fortunate that I'm with an organization that does care about you beyond your career," Cobb said. "And they've elaborated on the fact they appreciate what's gone on, what I've done for the organization in the past, and they're looking out for my best interest going forward from here. [It's special] that a team thinks like that and does want the best for me going forward.
"Just in conversation, it just seemed like a meaningless start [Thursday], and going into free agency there is always, every time you step onto the mound, the potential for some kind of incident to happen. Which I've seen in my career. Even if it's a small chance, it's a chance."
Cobb wouldn't say definitively that he will not be back, but he didn't dispute the idea that he wouldn't be back with the team next season.
"I guess it would be surprising," Cobb said. "Seeing how many guys have gone on once they hit the free-agent time period. Yeah, I guess surprising [is what it would be]."