The Dallas Mavs received a huge blow early in training camp, as forward Harrison Barnes tweaked his hamstring during Thursday's practice, expected to be “out for a while,” according to head coach Rick Carlisle, per Tim Cato of The Athletic.

Barnes is expected to miss all of the preseason, but he has yet to have a definitive timetable for his return.

The North Carolina product led the Mavericks in scoring and rebounding last season with 18.9 points and 6.1 rebounds per game.

His time on the sidelines will likely push second-year point guard Dennis Smith Jr. into a more active scoring role while giving rookie Luka Doncic more shots in this Dallas offense, which should set a solid start for his career.

The Mavericks will eventually need him back if they hope to sniff the playoffs at all this year, considering the ruthless competition with a murderer's row of championship contenders in the West.

Harrison Barnes put up career-highs in rebounds, assists, and free-throws attempted last season through his 77 starts with the team. He will no longer be expected to lead the team in rebounding after the acquisition of DeAndre Jordan, a top-five rebounder during the past five seasons, fresh off a career-high that saw him snatch 15.2 per game.