Just a month after the Miami Beach Commission approved a two-team competition to pick a developer for the city’s massive and oft-delayed convention center redevelopment plan, one commissioner has thrown a monkey wrench into the process.

Commissioner Deede Weithorn has asked for a “reconsideration’’ of last month’s 6-1 decision, which she supported, saying it was reached without sufficient analysis. Weithorn declined requests for an interview on Monday and Tuesday, saying she was too busy with her private business to talk, but she may be pushing for a third development team to be included in the competition.

Weithorn’s request, which she has asked the commission to consider at Wednesday’s meeting, has caused some head-scratching in City Hall and drawn consternation from the two competing development teams, both of which have already embarked on planning what are expected to be complex proposals for the redevelopment of 52 acres of city-owned land, including the aging convention center.

Jack Portman, a principal with the team ranked at the top by the city’s selection committee, on Tuesday called Weithorn’s rationale “absolutely ludicrious.” Portman said in an interview he’s concerned that investors he’s asking to sink hundreds of millions of dollars into the project will get cold feet if it’s subject to further delays.

The proposal has been dogged by concerns of bid-rigging, though prosecutors have said an investigation into the city’s former purchasing director has not turned up evidence of tainted bids.

“We’ve gone full speed ahead on the confidence that we have trust with the city, that we can count on their decision,’’ Portman said, adding that his team held a meeting of 35 consultants in Miami last week to begin developing its proposal, due by June. “What worries us is a retroactive vote on an issue that wasn’t even close. It makes us worry, what comes next?’’

“It’s a very complicated project. Everyone needs to know that both sides are solid and making rational decisions.’’

Victor Diaz, a lobbyist for the second team, South Beach ACE, did not return a phone call requesting comment.

At the Dec. 12 hearing, Weithorn had expressed concern that selecting just two teams out of the five applicants for the project would leave the city at a disadvantage if one were to drop out of the competition. A principal for the third-ranked team, David Edelstein, builder of the W Hotel on the Beach, argued strenuously during the hearing that the commission was making “a mistake’’ by not including his group in the contest.

But a commission majority, including Weithorn, went along with city administrators and selection committee members, who stressed the top two teams scored significantly better in their evaluations than Edelstein’s group, CConnectMB.

The decision to proceed came nearly a year after the city issued an open-ended request for proposals for a project to renovate the antiquated convention center, add an 800-room hotel and develop surrounding city property, possibly also including City Hall and the old Jackie Gleason Theater, with some mix of office, retail or residential buildings. The project, to be financed mostly with private money, could cost anywhere from $500 million to $1 billion, according to the city’s broad estimates.