"They're both on task," Rays manager Joe Maddon said. "I don't anticipate any setbacks."
Niemann threw four innings and 64 pitches while Davis threw three innings and 43 pitches.
"Right from the very beginning of the simulation, they went at it like they would [if they were on the mound in a regular game]," Rays pitching coach Jim Hickey said. "It wasn't like 15 fastballs to get into it. It was facing hitters."
The Rays hitters taking part in the simulated game included Kelly Shoppach, Reid Brignac, Sean Rodriguez and Dan Johnson. Shoppach managed to go deep against Niemann.
"It all went good, they threw all of their pitches at pretty much top effort and I thought it went extremely well," Hickey said.
"Barring some very unforeseen circumstance, they will start as we talked about; Davis first, on Tuesday, and Niemann on Wednesday."
Hickey said Friday's simulated game came as good news, but it affirmed Hickey's suspicion that both were going to be all right.
"I also had the feeling when this happened that they were serious enough to be put on the DL, but not real, real serious, where almost a 15, 16, 17 day break would be beneficial where they come back strong the last five or six weeks of the season," Hickey said. "So hopefully that will be the case.
"I think they both probably could have gotten by without missing a start. But this is just a little more of a forced rest, if you well, a little strengthening and rehabilitation and recharging of the batteries."
As for the home run he surrendered to Shoppach, Niemann said, "He's my catcher. I had to give him one."