City Council President Jimmy Ferrera last night put the brakes on the rush to move forward the city’s draft casino agreement with MGM.

It had been widely expected that the Council would approve the agreement, which Mayor Domenic Sarno had announced last week. “We can’t let the grass grow under our feet,” at-large Councilor Kateri Walsh told the Republican after Sarno’s announcement. But Ferrera tossed a monkey wrench in those plans by invoking Rule 20, which halts discussion on an issue until the city comptroller produces a report on the potential costs to the city.

After the meeting, Ferrera released a statement explaining the move. The potential casino project, he wrote, “is the largest financial issue, other than the city budget, to ever come before the City Council. This is an important opportunity for Springfield, perhaps even a crucial opportunity that can ensure our future. We need to get this right. By law, this document cannot be amended after we ratify it. There is no do-over.”

While he supports bringing a casino to the city, Ferrera continued, there are questions to be answered about MGM’s deal with the city, including the total amount of property taxes the project would yield, why the agreement has 1,200 fewer parking spots than originally proposed, and, most urgently, why it does not specifically describe the casino proposal as a $852 million project, as it earlier had been described. Instead, Ferrera noted, related documents now refer to the project’s “nearly $800 million investment.” That, he wrote, is a million less than the investment promised by rival casino developer Penn National, whose plan for the city’s North End was eliminated from contention last week by Sarno.

Ferrera will now face some backlash from people eager to see the casino project steam ahead. There will also, undoubtedly, be lots of speculation on the city’s back channels about whether he’s driven by some hidden agenda. I think that level of scrutiny is vital; given how much money is flying around the casino question, Springfield residents would be wise the look very closely at all the players and decision makers involved.

Still, whatever your personal theory about why Ferrera invoked Rule 20, it’s hard to argue with the case he’s made: if a casino does come to Springfield, it will change the city’s economy and culture in unprecedented ways. So why rush the process, which, as Ferrera notes, cannot be undone down the road. Why not pore over the agreement and get answers to lingering questions—including, as Ferrera contends, the apparent disappearance of $50 million from the original MGM proposal?

I’m not the only one to think Ferrera did the right thing: the casino-watchdog website CasinoWhispers.com is positively gushing with praise for Ferrera, calling him a “hero” and writing that “this plain spoken, earnest young man has done what few, if any, city officials have had the courage to do; stand up to MGM and their on-the-ground political arm twisters by saying ‘not so fast.’” (Indeed, CW’s praise is so effusive that I think I’ve finally uncovered the secret identity of the person behind the anonymous website: Ferrera’s mom.)

Ferrera’s delaying tactic aside, the Council is still moving ahead with its review of the MGM agreement; as Pete Goonan reports in today’s Republican, councilors will meet this Friday evening to discuss the deal.

Meanwhile, here’s another interesting detail to chew over: over his time on the Council, Ferrera has received a couple of thousand in campaign donations from members of the Callahan family, owners of Palmer Paving, the most recent in 2011. David Callahan is an investor in MGM’s casino project; he’s also president of Palmer Renewable Energy, which has a pending lawsuit against the city over the City Council’s revocation, in 2011, of a special permit for the controversial wood-burning power plant PRE has proposed in East Springfield. (Ferrera has been a supporter of the power plant project.) Ferrera has also received a couple of thousand dollars in donations from Callahan’s attorney, Frank Fitzgerald. The most recent: a $200 check on May 2, just a few days before Ferrera’s move to halt the MGM vote.

Callahan’s role in those two projects creates a particularly sticky situation: city officials are considering approving a major development deal in which he is involved at the same time they’re fighting a major lawsuit he’s filed against the city.