Arrieta was removed from Tuesday's starting assignment against the Minnesota Twins, with Kevin Gausman taking his place. Arrieta will pitch at Twin Lakes Park.
Asked if we could conclude that Arrieta is the fifth starter, Showalte replied, "No."
"We just haven't gotten there yet," Showalter added. "I'm not precluding him from being in the mix. I know you have to ask, but it's going to be a while."
Showalter also mentioned Brian Matusz, Steve Johnson, Jair Jurrjens and Rule 5 pick T.J. McFarland as possibilities for the rotation.
It's apparent that Jason Hammel, Wei-Yin Chen and Miguel Gonzalez will be in the rotation. Hammel is expected to be named the opening day starter.
"I'm not going to give an order right now, because we've got some things that might change that," Showalter said.
Chris Tillman is the variable. He's expected to break camp with the team, but the Orioles need to make sure he's accumulated enough innings this spring.
Tillman threw at Twin Lakes Park this morning, with pitching coach Rick Adair staying back to watch.
McFarland's chances of making the club would improve dramatically if Tillman started the season on the disabled list. At this point, the Orioles expect Tillman to be on the active roster.
Hammel, Jurrjens, Gausman and Tommy Hunter threw today in Sarasota.
Jurrjens is trying to make a late push to be included in the rotation. He tossed five scoreless innings in relief Friday in Port Charlotte, allowing only two hits.
Jurrjens' mechanics have improved and he has "a better base now," Showalter said. His body also is recovering faster after he pitches.
"He's come a long way," Showalter said.
The Orioles didn't make any cuts this morning. They could remove a few players from the camp roster later today, but Showalter wanted the extra bodies in Bradenton with the threat of rain in the forecast.
The Orioles still have 40 players on the roster, including pitcher Tsuyoshi Wada, who could be placed on the 60-day disabled list. Showalter indicated that a final decision hadn't been made, but it's expected to happen.