TUCSON, Ariz. -- D-backs manager Bob Melvin has decided on how the rotation will line up the first time through.

Well, sort of.

Melvin had previously said Brandon Webb, Dan Haren and Doug Davis would start the three-game season-opening series with the Reds, and on Thursday Melvin said Micah Owings, Edgar Gonzalez and Webb will be the starters in the following series in Denver.

Unless, of course it goes Owings, Webb and Gonzalez.

"Depending on whether or not we think we need to give Webb an extra day," Melvin said.

Webb will get an extra day one way or another the second time through the rotation, so rather than have him make back-to-back starts on extra rest, the D-backs may decide to go ahead and have him start that second game against the Rockies.

There's also the Randy Johnson factor to consider.

Johnson will start the year on the disabled list and pitch April 3 in Triple-A Tucson's season opener. It's likely that Johnson would need two Minor League starts, which means he could make his first big league start on April 14, give or take a day.

Where to put him in the rotation will not be as important a factor as his health.

"We could fit him in anywhere," Melvin said. "It's more about where we think he's best suited to pitch as opposed to who we should slot him behind. He can slot in anywhere."