The 28-year-old dislocated his hip during training camp and was feared to be lost for the entire campaign.
However, Harbaugh feels that the receiver could be a candidate for their short-term injured reserve list, which allows players to return at a designated point in the season.
He told the Baltimore Sun: "I think early next week we have to make that decision. I would say things are progressing favourably toward that. He's doing a really good job.
"I saw him today. He spent some time with [team owner] Steve Bisciotti today, too. He's working really hard. He's had no setbacks, and there's optimism.
"You've got to weigh that, you can't predict and deal in hypotheticals. Dennis is a great player. And this is an opportunity that seems like it might make sense."
Baltimore open their season against the Denver Broncos next Thursday.