In sports, “journeyman” often just means a lower-tier player. This is certainly the case in the individual sport of boxing, where “journeyman” is often a polite way of saying “tomato can”. But in team sports, “journeyman” often means a peculiar kind of athlete.
The two most stereotypical journeymen in baseball were pitchers Bobo Newsom and Mike Morgan.
From their Baseball Reference pages, I can say that that’s a lot of uniform numbers. The baseball player who currently holds the “record” for most teams played with is Edwin Jackson. So this kind of super-journeyman has to have a certain quality. They must not be bad enough that they simply drop out of the big leagues altogether after a comparably short and disappointing career, but they also can’t be good enough to have one team try and hold onto them. On that point, while free agency has allowed journeymen to move elsewhere on their own terms, the shuffled-around player definitely existed long before that-just ask Bobo Newsom himself, or all the other pre-1976 (when free agency began) baseball journeymen.
Some journeymen have unique skill sets. Jesse Orosco is perhaps the best example. With a pitch that was close to unhittable by left-handed batters, he became a “LOOGY” (Left Handed One Out Guy) who pitched into his mid forties as someone who showed up, threw to one or two batters, and then left the game.
To me, the journeyman offers a unique literary opportunity. The character can thrive at their sport and play for champion teams. But they aren’t a dominating superstar and live life on the edge in a way that said dominating superstar doesn’t. And they could go from a winner one day to a loser the next. The possibilities are massive.