The City of Detroit is helping Dan Gilbert and Tom Gores lure a Major League Soccer franchise to the city, Mayor Mike Duggan confirmed Thursday.

Duggan's affirmation of support in bringing a MLS franchise to Detroit came hours after the announcement of a tentative deal between the city and Wayne County to swap the massive 1.4-million-square-foot former American Motors headquarters in Detroit in exchange for 11 acres of city-owned land needed to build a new criminal justice complex near I-75.

Gilbert's Rock Ventures offered to build a $520.3-million complex for Wayne County, in exchange for the unfinished Gratiot jail site and surrounding justice buildings.

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Although the acquisition of the city-owned land was crucial in order to move Rock Ventures’ proposal forward, Duggan said the land swap is an entirely separate issue and not indicative of any progress made to build a soccer stadium at the unfinished jail site.

"I would not assume that at all," Duggan said in response to a Free Press question about the deal and stadium. "We need to get an MLS franchise but in my mind, this (the land swap) has nothing to do with a soccer stadium. This is a deal that is the right thing for the criminal justice center. Where the soccer stadium is located is a second question. We're pursuing an MLS franchise but there are a number of options for that, but I really can't say anything else."

Gores, owner of the Detroit Pistons, and Gilbert, owner of the Cleveland Cavaliers, announced a joint effort in late April to bring an MLS franchise to Detroit, with a preference to build a stadium on the site of the troubled Wayne County jail site on Gratiot.

Gilbert and Gores hope to build a 23,000-seat stadium at the site. The investment has been estimated at $1 billion. The application for an expansion team filed in January listed only the jail site as a location. Gilbert and Gores are one of a dozen groups that have submitted expansion bids to join MLS in 2020.

Gilbert has previously said that construction would begin March 6, 2018, and be completed Nov. 5, 2020.

The Free Press reported last month that an October presentation before MLS commissioner Don Garber and league representatives is looming for Detroit Pistons Vice Chairman Arn Tellem, who is spearheading Detroit’s bid for an MLS franchise. Tellem has remained bullish on the league’s potential impact on the city.

The agreement between Wayne County and the City of Detroit comes after officials told the Free Press last week that negotiations were ongoing and both sides were optimistic an agreement would be reached soon.

Gilbert's proposal for the city-owned land initially sought 13 acres of the 22-acre site, which is bounded by the I-75 service drive and East Warren Avenue, and includes Detroit Department of Transportation administrative offices.

But officials said Thursday the deal is now for just slightly over 11 acres behind DDOT's bus terminal, ensuring the transit's operations won't be impacted.

Duggan said Thursday he believes the land is an "ideal place" for a criminal justice center.

"I think you'll see restaurants and other development for jurors and witnesses and lawyers and the like," Duggan said. "The county executive said that was a site he wanted to nail down as an option. He hasn't made a final decision."

The deal would enable the city to acquire the 1.4-million-square-foot complex of the former American Motors headquarters on Plymouth Road on Detroit's west side, which is currently owned by the Wayne County Land Bank.

Duggan said the city plans to market the old headquarters for re-development but the subsequent purchase agreement must first clear hurdles of approval by the Detroit City Council, Wayne County Commission and the Wayne County Land Bank Board.

" ... The old AMC property on Plymouth Road is a serious source of blight in that neighborhood, and I'd like to target the redevelopment of the AMC property as one of our highest priorities," Duggan said. "We've got a year or so to do a review and make sure the environmental (assessments) are OK and if there's a problem, we can elect to take $757,000."

According to the agreement, Detroit has the option to forgo swapping the land and instead opt to receive the fair market value of the city property from Wayne County, which is estimated to be $757,000. The city has until Nov. 1, 2018, to make that selection.

Duggan said the agreement still has to be approved by the Detroit City Council, Wayne County Commission and Wayne County Land Bank Board. Duggan said he expects the agreement to be before council relatively soon.

In terms of plans for the former American Motors property, Duggan declined to elaborate but said it's time for it to be redeveloped.

"I have some plans for it but I really don't want to talk about it right now but if you drive by there you've got a neighborhood that is a quality neighborhood with some parks nearby and they're looking at this huge building where George Romney used to work and has been empty almost since then," Duggan said. "We need to address it. We do think we have good plans to address it. We think we have the resources to address it and this is going to work out for both of us."

Katrease Stafford: kstafford@freepress.com or 313-223-4759. Staff writer Vince Ellis contributed to this report.