FR lawmakers Daniel Arroyo, Fernando Asencio and Jorge Taboada will also split from Massa, forming a new alliance with the Movimiento Evita and lawmaker Victoria Donda, who was informally allied with Massa.
The decision will be announced at a press conference in Buenos Aires on Monday afternoon, sources told the Noticias Argentinas (NA) news agency.
Solá, the former governor of Buenos Aires province, has long expressed his intentions to run for the presidency in 2019. He will lead the new voting bloc, sources told NA.
The move is unsurprising given Solá's change of tone toward Fernández de Kirchner in recent years. In the last 12 months, he has — without the endorsement of the FR or Sergio Massa — been seen alongside Victory Front (FpV) lawmakers at panels, conferences and meetings aimed at securing "unity".
"I don't want to go to an election with two Peronisms. Whoever is working toward there being two Peronisms is working for [President Mauricio] Macri. And I want to beat Macri, representing a united Peronism", Solá said in July.
Massa was seen in Tucumán province with former presidential candidate-cum-lamwaker Daniel Scioli, who sits with Fernández de Kirchner's voting bloc in the Lower House, while hardcore Kirchnerites who control Peronism's party structure, the PJ, huddled in Corrientes.
Despite Monday's reshuffle, Massa's key congressional ally Graciela Camaño on Sunday said the Peronist movement could go to the 2019 elections with an alliance "as broad as to include all political leaders who want to represent an opposition to the government's economic model".
"On the streets, they're telling us: 'Come together so things change'", she told Radio Cooperative's AM 770.