Bob Sleigh, leader of Solihull council, said he intended to seek its approval for talks in principle.
The councils controlling Birmingham, Walsall, Sandwell, Wolverhampton, Coventry and Dudley have backed the combined authority proposal.
Cities may be in line for new housing, transport, planning and policing powers if they sign up for devolution plans.
Chancellor George Osborne said on Thursday that Greater Manchester should become a blueprint for other large cities.
There, leaders of 10 councils work together as part of combined authority and there are plans to elect a mayor for the entire area in two years.
Labour claimed the government's "piecemeal approach" could mask big cuts to local councils' spending.
On 14 July Solihull's full council will debate the plan to join other West Midlands authorities in talks over a proposed combined authority.
Mr Sleigh said he told full council he intended to seek approval "for taking forward detailed discussions in principle" to support a combined authority.
He said to achieve Solihull's ambition for sustainable economic growth, the borough "needs a high-performing regional platform of a scale and geography that attracts the significant inward investment needed to satisfy that ambition".
Council leaders have previously said the combined authority, which could serve four million people, would help attract investment worth hundreds of millions of pounds.

So-called Islamic State (IS) is most prominent in the region, but there are at least two other groups, with possible links to Islamic State's arch-rival, al-Qaeda, worth paying attention to.
This is the name of IS' Sinai affiliate. It has claimed responsibility for downing the Russian airliner.
Formerly known as Ansar Beit al-Maqdis, the group first appeared in September 2011 and rebranded itself with an Islamic State pledge of allegiance in November 2014.
It generally targets Egyptian military and security forces in northern Sinai, and has scaled up attacks since July when it claimed an attack on a naval vessel in the Red Sea.
The propaganda of this low-profile group suggests alignment with al-Qaeda.
It posted a sophisticated video two days before the Sinai plane crash showcasing its strengths, but without any specific threats.
Jund al-Islam emerged in September 2013 with a claim of a double suicide attack on the Egyptian military intelligence HQ in the north Sinai town of Rafah, on the border with the Gaza Strip.
It has stepped up its propaganda campaign this year, claiming rocket attacks on Israel, and its latest video hints at links with al-Qaeda in Yemen - which has a record of trying to down planes.
Online jihadist media operatives have also suggested that al-Qaeda in Yemen has been given oversight of activities in Egypt, among other regional fronts.
Not to be confused with established Saharan group Al-Mourabitoun, this Egyptian faction announced itself in July.
Its propaganda suggests an al-Qaeda orientation, and veteran jihadist media operatives link it - along with Jund al-Islam  - to an al-Qaeda attempt to check the rise of Islamic State in Egypt.
Its leader, Abu-Umar al-Muhajir alias Hisham Ashmawi, is a former officer in the Egyptian army, and was a senior figure in Ansar Beit al-Maqdis before it pledged allegiance to Islamic State.
In October, Ashmawi issued a call for the killing of Egyptian military officers, and for revenge for the deaths of Palestinians by Israel's security forces.
Meaning "Soldiers of Egypt", this group appeared in January 2014, and carried out attacks in Cairo over the summer.
It has possible al-Qaeda associations, in that the Yemeni and African branches of that network posted eulogies on the death of its leader in April.
It also coordinated attacks with Ansar Beit al-Maqdis before the latter joined Islamic State.
But Ajnad Misr has repeatedly said that it tries to avoid civilian casualties in its attacks.
The Al-Furqan Brigade and the salafist-jihadist Group in Sinai appear to be dormant, beyond issuing online threats against the Egyptian state.
BBC Monitoring reports and analyses news from TV, radio, web and print media around the world. You can follow BBC Monitoring  on Twitter and Facebook.
Solihull has moved closer to joining the proposal for a West Midlands combined authority.
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The Sinai plane crash has drawn international media attention to Islamist armed groups active in the Sinai Peninsula.