Zig Zagged: Bob defeats a powerful opponent, who turns out to be Only Mostly Dead. After this, Bob unveils an Eleventh Hour Superpower, in which he defeats the opponent again, only for them to get back up...
Averted: Bob isn't a jobber and instead has a normal win-loss record.
Enforced: "Hey, we need to show off how powerful this new opponent is! I know, put him up against Bob!"
Lampshaded: "Can't I ever win a fight?"
Invoked: Charlie decides to intimidate Alice with his new powers and chooses the strongest member of her team, Bob, to destroy first.
Exploited: New characters deliberately attack Bob, knowing that most chances are that he'll lose.
Defied: Bob, fighting a critical battle, decides to shed his role as a jobber once and for all.
Discussed: "So, has Bob ever won a fight for this team?"
Conversed: Bob and Alice are doctors, and while sitting in the lounge, the topic turns to Bob's impressive musculature, at which point Alice comments, "But, then again, it means you're the first one to get knocked out if a supervillain shows up".
Deconstructed: Bob realizes that he's ultimately a jobber, and this starts to take a mental and emotional toll on him, leading him to quit...
...However, he decides that his purpose is to lose so his teammates can learn the fighting styles of his opponents, and rejoins.
Bob chooses to learn from Charlie about his strength and weakness.
Bob accepts that he is Overshadowed by Awesome and deliberately fights using a highly defensive style to tire his opponents rather than defeat them. When the time is right, he wisely retreats so The Hero can do his job.
Bob actually handles a few of them; the tougher ones, though...