I'm not saying they're tanking ... but they're tanking, lol.
Though really I wonder what is the benefit of bringing him back this late in the season. If he reaggravates the knee or ankle it could require another 2+ months to fix or even surgery which will mean the entire off-season of training for him is a wash.
If the games actually mattered then yeah I'd bring him back, but at this juncture ... really what's the point I suppose. There's more risk than reward.
I suspect too that he actually does need season ending knee surgery. He just gutted it out and played through pain rather than giving up on the season.
If he did need surgery and they were aware of it they would have done it once he was out due to the ankle injury I'd imagine.
Unless the two injuries would conflict with each other in terms of rehabilitation. Might be you need the ankle healthy before you could do surgery+rehab on the knee.