They are even thinner Thursday.
"Yeah, we are," Phillies general manager Ruben Amaro Jr. said. "We've talked about it. That's one of the things we don't have: A lot of pitching depth. We have some bullpen depth, but we don't have a lot of starting pitching depth.
"There's a hole in there between the Major Leagues and [Class] A ball, where there aren't a lot of candidates for us. That's part of the risk of making some of the trades we've made. It's kind of what happens when you make a run for things and you try to improve your club at the Major League level. This is where we've sacrificed, and hopefully we can kind of weather the storm here a little bit."
The Phils said Blanton will begin the season on the 15-day disabled list after straining his oblique throwing in the bullpen. He is expected to miss three to six weeks. Right-hander Kyle Kendrick will take Blanton's spot in the rotation and pitch next Thursday against Washington, and right-hander Andrew Carpenter is expected to take Kendrick's place in the bullpen, although Philadelphia does not have to finalize its 25-man roster until 3 p.m. ET on Sunday.
The Phillies are not expected to find pitching help from outside the organization before Opening Day on Monday afternoon in Washington.
"If we had another guy go down right now, we'd be scrambling a little bit," Amaro said.
Carpenter might follow Kendrick into the rotation at that point. Ryan Vogelsong also has big league experience. Josh Fogg? The Phillies just signed him to a Minor League contract, but he is not considered an option.
Who else is there?
"There aren't a lot of them, and it puts us in a tough spot," Amaro said. "But we have been looking out there on the waiver wire. We have been looking at other clubs. The problem is, they're looking for the same sort of thing."
Free-agent right-hander Pedro Martinez remains on the radar -- the Phillies have been talking with Martinez's agent since December -- although if negotiations heat up, it likely would happen closer to midseason.
But Blanton's injury not only impacts the rotation, it also impacts the bullpen. The 'pen already is frail without Lidge and J.C. Romero, who both will open the season on the disabled list. They will be eligible to be activated April 10 in Houston, although it is more likely they will be ready no earlier than the second or third week of April.
Kendrick's presence in the bullpen before Blanton's injury at least provided the Phillies more stability. Kendrick could have followed J.A. Happ's path last season. Happ pitched himself into a prominent role in the bullpen until he replaced right-hander Chan Ho Park in the rotation. Now the Phils have only four veterans in the 'pen to open the season: Ryan Madson, Danys Baez, Chad Durbin and Jose Contreras -- and nobody knows what the Phillies will get from Baez or Contreras.
The other three bullpen spots will be filled by rookies David Herndon, Antonio Bastardo and Carpenter.
The Phils will have to hope their starters pitch well the first month of the season until Blanton, Lidge and Romero return.
"Until we get our bullpen established, and until we see what we've got, it's very important that our starters go deep in the game," manager Charlie Manuel said. "If you can go seven or eight innings, the more the better."
Blanton, who will be on the DL for the first time in his career, said he felt a sharp pain throwing a pitch Wednesday. He rested about 30 seconds and tried to throw again.
"It felt like somebody stabbed me with a knife in my side, so I shut it down," he said.
Blanton knows he must be careful during his rehab. Players can injure the oblique again if they try to come back too quickly. Otherwise, the Phillies seemed fairly optimistic Blanton could return closer to three weeks than six.
In the meantime, the club will have to work with what it has.
And if a need for pitching lingers later into the season?
"We have the pieces," Amaro said. "Absolutely, we have the pieces. I guess our druthers are to let these guys play and play successfully and not have holes. But we'll deal with that when the time comes. I don't have a crystal ball. ... But you can't cover every single mishap. Injuries are part of the game. We're not going to be able to replace All-Stars with All-Stars. It ain't happening. But hopefully we have enough pieces and enough depth on the field at the Major League level and below to kind of carry us."
Todd Zolecki is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.