Cuba’s next Armed Forces Minister will be an old comrade-in-arms of Raúl Castro. Or a younger man whose selection will hint at the island’s future leadership. Or a hardliner who will not hesitate to crush street riots.

And that is only part of the many strains of speculation sparked by the death last week of Gen. Julio Casas Regueiro, who succeeded Castro at the head of the Armed Forces Ministry (MINFAR) in 2008.

Casas, 75, fought alongside Castro in the guerrilla war against the Batista dictatorship and was long considered his most loyal No. 2 as well as MINFAR’s economic brain. He died from a reported heart attack.

Cuba watchers agree the job is critical: MINFAR now controls 60 percent of the economy, and its loyalty is required for Castro’s risky attempts to inject market efficiencies into the Soviet-styled economy.

The best candidate would appear to be Gen. Leopoldo Cintra Frías, 70, another veteran of the anti-Batista fight who is now first vice minister of the armed forces and a member of the Cuba’s ruling Council of State.

Also mentioned as possibilities are two MINFAR vice ministers: Gen. Alvaro Lopez Miera, 68, who also serves as Chief of Staff of the armed forces; and Gen. Ramón Espinosa Martín, 72.

On the list of long-shots are Gen. Abelardo “Furry” Colomé Ibarra, a long-time MINFAR officer before he was appointed as Interior Minister; and Gen. Ulises Rosales del Toro, a former MINFAR first vice-minister who more recently has run Cuba’s sugar industry.

Popular blogger Yoani Sánchez wrote last week that “the most pessimist” of speculators also mention Castro’s son, Col. Alejandro Castro Espín, as a possibility.

Eugenio Yanez, a Miami exile who writes often on the Cuban military, published a column arguing that Casas’ successor will have to meet two conditions.

“A promise to not hesitate if there’s an order to send the army into the streets to control a crisis,” he wrote, “and an assurance that no conspiracies against those in power will emerge from the armed forces.”

Since the U.S. army clearly is not about to invade Cuba, “the armed forces minister therefore does not have to be a military genius as much as a guarantor for those in power,” Yanez wrote in the website Cubaencuentro.

Arturo Lopez Levy, a former MININT analyst now at the University of Denver, wrote on the Web site Infolatam that Casas’ death sends two messages to the 80-year old Castro: He has a limited time to arrange the Cuban government’s generational changing of the guard and that he must consider the age and health of his own possible successor.

Yanez added a “wild card” to his list of possibilities: Ramiro Valdez, 78, a hardliner whose experience managing large state enterprises might serve him well at MINFAR, although he has clashed with Raúl Castro in the past.

“Everyone knows that he would not hesitate to ‘send the tanks into the streets’ if it was needed,” Yanez wrote. “Would he send them out against Raúl Castro?”