Firts, understand that a "medical redshirt" can only occur when the college you are attending asks for and receives a hardship waiver. You can't do this by yourself, and if you play baseball after leaving the JC, the process will likely have to be repeated in order to satisfy the rules of the NAIA or NCAA.
Secondly, "likely will sit out" isn't sufficient. Every sanctioning body for college baseball (NJCAA, CCCAA, NAIA, NCAA) require that the injury be season ending, and a doctor (not a chiropractor) must at the time of the injury certify in writing that the injury incapacitates the player for the rest of the season. If you can get such "contemporaneous documentation", go ahead and do it. It probably won't allow a waiver at the JC, but may allow one later at a D2 or NAIA school.
It's close, but if your assessment of games played turns out to be the actual situation (no games made up), then you have competed in the second half of the season, because game 26 takes place in both the first and second half a 51 game season. That would disqualify you for a hardship waiver at a NJCAA, D3, or D1 school. But D2 and NAIA could issue a waiver if you eventually transfer to one of those schools.
The 3 games are easily under the limit for all sanctioning groups.
The concussion was demonstrably not season ending, and has no further bearing on a hardship case.
So,
1) If your present injury is season ending, and a doctor can provide that documentation, get and keep the documentation. Do this even if your JC doesn't think it is important.
2) Since you have apparently played after the beginning of the second half of the season, this season will count as 1 of the 2 allowed seasons at a JC, even if 1) is satisfied.
3) Similarly, this season will count against the 4 that are allowed at D1 and D3 schools.
4) If you have the documentation mentioned in 1), then you probably can get a waiver so that this season won't count at a D2 or NAIA school.
All of this hinges on two points: The injury needs to be documented as season ending, or no waiver can be granted. For D1/D3 and JC, all of the games you played in must have been in the first half.
