Rays manager Kevin Cash allowed that "it was very difficult" to tell Moore on Saturday.
"Matt handled it exceptionally well," Cash said. "I think he understood where we were coming from. A lot has to do with his best interest. But it was a difficult conversation to have. And I think the messages that were given to him and the ones that he gave back were beneficial. We're going to come up with a plan -- what's best for him while he's down there."
Cash said pitching coach Jim Hickey, bullpen coach Stan Boroski, and Durham pitching coach Kyle Snyder will all be involved in helping Moore find his way.
Moore made his sixth start in Saturday's 11-7 loss to the Red Sox, allowing six runs on nine hits and a walk with two strikeouts. Though Moore worked just three innings, he threw 70 pitches (46 strikes). He is 1-3 with an 8.78 ERA for the season.
Cash said several factors came into play in making the decision.
"One, this is the first time we've had an opportunity to go to a four-man rotation," Cash said. "It's definitely not fair to ask Matt Moore to go into the bullpen. We need to get his innings on a consistent track, because that factors into what he's capable of doing next year for us.
"But most importantly, we need to get Matt back to being the guy that he is. We know, as an organization going forward, he's a huge part of what we're doing. And I think this stability, keeping him on his five days, will help."
While Moore's return to the team once a fifth starter is needed is certainly a possibility, Cash noted that Moore is not on a predetermined schedule.
"There's no timetable on anybody coming back," Cash said. "We've got other guys who could potentially come back. I think we've got about a 17-20-game stretch here with the off-days where a four-man rotation is possible."