One of the depth solutions may be Jesse Puljujarvi, who was drafted 4th overall in 2016 and has been unable to live up to expectations. As a result, he's alternated between the Oilers roster and even returned home to Finland for some time before trying his luck again in the NHL.
It is obvious that McLellan needs depth on a roster that isn't stacked and will need to be rebuilt eventually. On a PTO, Puljujarvi can prove himself in depth and solve another Capitals' problem by proving himself as a depth player.