The Patriots signed veteran quarterback Brian Hoyer in free agency after losing Brady.
Barring unforeseen circumstances, Stidham appears to have the inside track on the starting job, Howe adds.
Newton, 30, was making around $20 million annually after he signed a five-year, $103.8-million extension with Carolina in 2015. The Panthers released the former MVP earlier this offseason after nine campaigns.
Dalton, meanwhile, is still under contract with the Bengals, but Cincinnati is reportedly helping the veteran signal-caller work out a trade. The 32-year-old is signed through 2020 and is set to make $17.7 million in 2020.
New England currently ranks 31st in the league with less than $709,000 in salary-cap space, according to Over The Cap.