General manager John Hammond said Monday that the 21-year-old Jennings was examined after Saturday's 95-86 loss to Utah.
Jennings broke the long bone on the outside of his left foot that connects to the little toe, one of the most common bones to break in the foot. He earlier said he first felt pain in a loss to San Antonio, but kept playing and also played 30 minutes against the Jazz.
"I think it shows you a lot about Brandon, the people who haven't had a chance to watch him in his first year and a quarter, I don't think anyone is going to question his competitive spirit," Hammond said.
Jennings had started every game since being picked 10th overall in 2009, a string of 107 regular-season games and seven in the postseason. He'd been averaging 17.9 points per game and 5.5 assists in 25 games this year.
Jennings said earlier in the week that he hurt himself on a drive to the basket against the Spurs when he came down awkwardly on his knee and it put pressure on his ankle. Against the Jazz, he went 3 of 7 from the field and finished with six points, four assists and three rebounds.
"We know we can trust him and we know he's going to be a guy who's going to come back as soon as he's capable and ready," Hammond said. "We know he's tough enough to handle the assignment."
Jennings seemed like he was in good spirits, too, for his surgery. He posted pictures of himself in the hospital online, including his wristband for admission and some of the hospital clothing he'd be wearing.
Dooling will take Jennings' spot in the lineup when Milwaukee begins a three-game road trip in Portland on Monday night. Other stops include the Lakers on Tuesday and Sacramento on Thursday.
"Most teams try to have three point guards and this is one of the reasons why," Hammond said. "It's a combination that we'll move forward with."
Forwards Corey Maggette and Carlos Delfino are also not on this trip after both have had symptoms of concussions. Maggette fell and hit his head against Utah, while Delfino sustained a concussion the second game of the season at Minnesota and has missed 18 games.
"No one's going to feel sorry for us," Hammond said. "We still have a job to do, that's win every game that we take floor."