Liverpool had plenty of injuries last season. When everyone was fit, he wasn't first name off the bench.
Henderson missed 7 games last season through injury
Oxlade-Chamberlain missed 5 games (same time as Can was injured)
Wijnaldum missed 0 games
Milner missed 0 games
Grujic missed 0 games
Lallana missed 32 games, although he's not a CM player
So basically Can with his 11 games was the most injured CM for Liverpool last season, yet he was apparently only starting because other players were injured. So Can has done quite well there considering he wasn't even first name off the bench (probably because he was in the starting XI most weeks).
I think what you should say is that generally Liverpool were fairly light last season with midfield numbers and quality, and then they went and spent €100m+ on two CM players.