This. Silva hasn't meant to touch it otherwise like you said do players suddenly becomes onside if it deflects from a defender. Don't really get it.I think the rule is if it's touched by a teammate, but in practice it means the teammate actually putting the ball through.
Otherwise, if the rule is the last player who touches the ball counts, then any pass that gets a nick off a defender would mean the striker was onside?
Common sense tells me that Eriksen has played the pass, it's a deflection off the City player and therefore it should be onside because there's no deliberate action from a City player to give an assist.