Probably a wise decision really, given where his fitness was at before lockdown, he was never gonna return to training match fit.
We're well stocked in midfield anyway, and as talented a player as he clearly is, he's been way off match fit, and has now been sat around for months, only doing general fitness routines at home, so will be even further from match fit now.
The other players in the squad will find it a lot easier to get back to where they were before lockdown, as they were already in tip top condition, and with his injury problems, it's not worth putting him through an intensive training period, only to hardly use him for these 2 or 3 games anyway, as he'll never get up to speed in time, and could get injured trying.
It doesn't sound like he's injured again, so if thats the case, he's actually been injury free for a long time, and probably had a productive fitness program and a good refreshing rest during lockdown, which will benefit him greatly, and if he's gonna stand any chance of salvaging his career and playing regularly again next season, (hopefully for us) it's best he slowly builds his fitness up over time, gets himself strong and fit again, and plans for next season.
IF he can do that, then he's worth taking a punt on with a pay as you play deal for next season, as if he's fully fit, he'll be a great player to have in the squad.