While playing on an abysmal San Jose Sharks team, Ferraro has looked decent. While he has only posted 4 points in 26 games, he leads his team in TOI with an average of 22:12, so he is accustomed to playing big minutes.
His +/- has been very poor but that's to be expected playing huge minutes on a brutal team. Ferraro could make a positive impact on the Oilers back end, assuming the price to acquire isn't too high. He carries an AAV of 3.25 million, which would likely be doable with the Klingberg money off the books.