Bellisario, who ended up casting him in later CBS shows JAG and First Monday As Stockwell's Quantum Leap co-star Scott Bakula posted his tribute in Deadline Hollywood so did Bellisario.
NBC Universal
Quantum Leap Creator Donald P Bellisario's Statement
Dean and I were both in our mid-fifties when I hired him to play the smart-mouthed hologram Al Calavicci[...]