いるだろう

will probably be

→ 居る
phrase Rare #29,341
will probably be だろう expresses a guess or expectation. After a verb ending in ている, the phrase often means that an action will probably be completed or ongoing by a particular time.
JA: 彼はもう家に着いているだろう。
EN: He has probably arrived home by now.

彼女は今頃もうパリに着いているだろう。

She should have arrived in Paris by now.

彼は明日に今頃、彼女と夕食を食べているだろう。

By this time tomorrow, he'll be having dinner with her.

彼は明日までには宿題を終えているだろう。

He will have finished his homework by tomorrow.

彼は今頃もう大阪に着いているだろう。

He should have arrived in Osaka by now.

君が戻るまでには彼はここをたってしまっているだろう。

He’ll have left here by the time you get back.

君が帰る前に彼女はいなくなっているだろう。

She will be gone before you get home.