As others in this thread have pointed out it’s not necessarily a good approach for healing a tendon, and could be counterproductive.
Back in the day when designer “pro-steroids” (basically tweaked pro-hormones that metabolized into anabolic steroids in the body) were widely and legally available from supplement manufacturers, I had a bone graft surgery scheduled and wrote to the chemist who had developed one of the better products to get advice on a cycle for my recovery. This is anecdotal of course, but my surgeon told me that when she was fixing up the bone she realized it was in worse shape than the MRI had indicated and she puts the odds of success at 50/50. She was amazed at the speed and completeness of my recovery. I still have Frankenstein scars where the stitches were because my skin had “healed so quickly” that the stitches were difficult to remove and left gnarly holes.
I like to think that the supplement tipped the odds in my favour. Despite the well-established benefits of anabolic steroids on bone healing, the stigma around them means they are almost never prescribed even in bad cases. YMMV, but other than a few friends commenting that I a bit of an asshole while on the cycle (which could have just been the misery of post-surgery), I suffered no ill after-effects and actually put on a few pounds of lean mass despite being largely convalescent.
And it seems there is good reason to have it be a prescription: Some of the side effects aren't wonderful and it would seem reasonable to at least get regular blood tests if you are taking it. It is just benefits sometimes outweigh the risks.
See it come across as "I got 2nd place in a men's triathlon. I found out the winner is on TRT, which is not allowed. How do I get them DQed so that I can rightly claim my medal?"
Which to me makes sense, but age groupers don't get any blood testing done, so it's a bit of a he-said she-said thing.
Why not just slowly taper it off?
1. https://en.wikipedia.org/wiki/Selective_androgen_receptor_mo...
Also there are several steroids with different half-lives, so you can pick the best for your case.
The issue is compliance - nobody really wants to inject themselves every day or every other day.
(Well, I know why—like you said, compliance. But c’mon, left cheek on Monday, right check on Thursday, easy enough.)
As a result, when you end your cycle, your body needs to restart its natural test production. There can be a delay while this happens and it leads to unpleasant, though temporary, side effects, like weight gain and a loss of sexual appetite. This can be mitigated somewhat by taking estrogen regulators such as Clomid, which is a prescription drug for women.
Anyway, the upshot of all this is injecting steroids in men is sort of complicated. For your rehab scenario, your doctor would have to monitor your test and estrogen levels as you end your cycle. For moderate cycles like with your calf rehab, the dangers are vastly overblown in the media, but the short-term side effects can be bothersome.
Note that women don’t face these issues and indeed women can take convenient oral steroids like eg Winstrol without having to inject test to compensate for their natural production getting shut down, because they hardly have any natural production to begin with. Indeed, ethics aside, the arguments for women to do a very moderate cycle for your rehab scenario or just athletic performance are pretty strong.