But he could say J.A. Happ will remain in the rotation the remainder of the season.
"Happ's not going anywhere," Amaro said. "He's not going out of the rotation. He deserves to stay in the rotation. He has pitched very well. He's one of our most effective starters."
Those words came less than 24 hours after Happ threw his second shutout of the season, a 7-0 victory Wednesday against the Rockies. Happ is 8-2 with a 2.74 ERA, which ranks sixth in the National League. Martinez walked none and struck out 11 in a rehab start Wednesday with Double-A Reading. Martinez's imminent arrival gives the Phillies six starters: Cliff Lee, Cole Hamels, Joe Blanton, Jamie Moyer, Happ and Martinez.
"It is [a relief]," Happ said. "I don't really want it to be that big of a story, but I don't know what's going to happen."
So if Happ remains in the rotation, that means Moyer or Martinez are out, right?
"Why can't we go with a six-man rotation?" Amaro said.
It is possible, but there appear to be drawbacks to a six-man rotation:
The Phillies have three of their next four Mondays off. That would leave starters pitching about once a week through the end of the month.
A six-man rotation would give the team's best pitchers fewer opportunities to pitch. Say the Phillies go to a six-man rotation beginning Tuesday in Chicago. That would give each starter an average of 8.8 more starts the remainder of the season. A five-man rotation would give them an average of 10.6 more starts. It would seem to be in the Phillies' best interests to give Lee, Blanton, Hamels and Happ as many starts as possible.
"It depends how you utilize it," Amaro said of a six-man rotation. "You can be creative and set up the rotation so certain guys go every five days and other guys are pushed back. The fact of the matter is we're not there yet. But we are in a situation where we have six starters, and we'll see how creative we can be. We haven't discussed it yet. You never know what's going to happen over the next week to 10 days. We could have a guy go down right now. There are a lot of things that could happen over the next week to 10 days that could change our thinking completely."
If the Phillies stick with a five-man rotation, Moyer could be the odd man out. He leads the team with 10 wins, but his 5.55 ERA is the second highest in the NL. Martinez has not pitched in the Majors since last season, but the Phils have reiterated that Martinez's future is in the rotation, though he has bonuses in his contract based on relief appearances.
But this is a very tricky situation for Philadelphia.
Moyer, 46, has won 256 games in his career. Martinez is a three-time Cy Young Award winner. These aren't typical pitchers.
"They deserve a tremendous amount of respect for what they've done in the game," Amaro said. "And they will get our respect in that regard. At the same time, we have to do what's best for our club to win baseball games. We're in the business of winning. It's not necessarily about hurting people's feelings. It's really about trying to make the right baseball decision for our club."
Martinez said Wednesday he does not need another rehab start. He allowed five hits, four runs (three earned), no walks and struck out 11 in six innings. He threw 82 pitches. His fastball ranged from 86 to 92 mph, but averaged 90 to 91 mph in the sixth.
"I hope there's no more," said Martinez, who who will throw a bullpen session with the Phillies on Friday.
Amaro, who watched Martinez pitch, said he came away impressed, but said the club has not decided if Martinez needs another rehab start.
"He threw strikes. He commanded all his pitches," Amaro said. "Frankly, I thought he threw quite well."
Of course, Martinez pitched against the Trenton Thunder. The Cubs, whom he could face next week, are much better.
"Oh, I think he can get Major League hitters out with his stuff," Amaro said. "I know it was a Double-A club, but no walks and 11 punchouts -- that's good in Little League."
Todd Zolecki is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.