Regular skipper Connor Rozee has played just two games this season, tearing a hamstring tendon and damaging nerves.
His vice-captain Zak Butters stepped up, but now the triple club champion is long odds to play again this season because of an ankle injury.
Soon to fall off-contract, Butters' future at Port remains in limbo as he weighs some of the biggest deals in AFL history to return to his native Victoria.
Horne-Francis, 23, last week spoke of his desire to one day captain the Power, but hierarchy have opted for Drew, a 147-gamer who shared the vice-captaincy with Butters.
Drew remains an unsung regular in his seventh season at Port, but is held in high esteem by teammates, including Miles Bergman.
"He has been such a great leader of the club for such a long time now," Bergman told reporters on Wednesday.
"He's well loved amongst the group, and he drives the standards game day and is always pushing the boys throughout training.
"So it will be really good to see how he leads ... we're all excited about what he's got to bring."
Port's stocks have also been hit by a concussion to chief goalkicker Mitch Georgiades, who will miss Saturday's home game against red-hot ladder leaders Fremantle.
Defender Lachie Jones (ribs) faces a fitness test, Jack Lukosius is again out because of fluid behind a knee and calf issues and captain Rozee is among seven players ruled out for the year.
"It's obviously tough, a lot of sore boys and a lot of injured boys coming into the start of the week," Bergman said.
"But we've been driving really hard on positive attitude and driving the energy around the club.
"We're just optimistic with all the opportunities we get with new people coming in, new roles played and that sort of thing."
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