The Camp Nou icon has been absent so far this season due to a calf injury, but Barcelona's official website confirmed medical staff gave Messi the green light after he trained on Monday. He has been included in the squad that will travel to Germany.
Barcelona lost their first game of the season 1-0 away to Athletic Bilbao, but they've since gone unbeaten in three and scored 12 goals in that span.
Dortmund lost 3-1 at Union Berlin before the international break but bounced back with a 4-0 victory over Bayer Leverkusen in their return to Bundesliga action on Saturday.
Messi had several injuries last season and was sidelined for three weeks after fracturing his right arm in October 2018. He also suffered a groin injury in March that kept him out of action for Argentina's friendly against Morocco.
The 32-year-old has played at least 49 matches in all but one of his previous 10 seasons at Barcelona—he played only 46 matches in 2013-14, per Transfermarkt.
The South American was again instrumental for Barcelona last season and scored 51 goals in 50 appearances for Ernesto Valverde's side.
The coach will welcome the return of his biggest star after Barca have been forced to rely on reserve options, with Luis Suarez only making his return to fitness in Saturday's 5-1 win over Valencia.