FORT LAUDERDALE, Fla. -- The Twins knew there would be some uncertainties surrounding their rotation heading into the 2008 season.

But Scott Baker's setbacks this spring and Francisco Liriano's uncertain status have left the Twins with a few more question marks about their rotation than expected.

The issues with the duo are concerning, but perhaps not as much as one may think. That's because a few pitchers have stepped up to become legitimate rotation candidates in recent weeks.

Three of those pitchers -- right-handers Philip Humber and Nick Blackburn and left-hander Glen Perkins -- were on the mound in Tuesday's 4-2 victory over the Orioles.

And after the game, Twins manager Ron Gardenhire said what he's seeing from some of the young arms is somewhat comforting considering the club's current situation.

"They are all throwing really good and they are making decisions very tough -- which is good because we need that," Gardenhire said. "We've got people hurt and people we don't know about, so the more depth you can have right now the better."

Earlier in spring camp, it had appeared that the team was looking to fill just the fifth spot in the rotation. Livan Hernandez, Boof Bonser, Baker and Liriano all seemed to have their rotation spots pretty much locked up -- that is, as long as Liriano was deemed to be healthy.

Baker has suffered a few setbacks due to his strained back muscle and recent bout with the flu, and Liriano's progress has been delayed some by his late arrival to camp and his slow comeback from Tommy John ligament replacement surgery on his left elbow.

So the Twins could end up needing more than one of their other young arms to step up and fill the holes.

One pitcher who has been making a strong push for the rotation of late has been Humber, the most Major League ready of the three pitchers the Twins received from the Mets in the Johan Santana trade.

After tossing nine straight scoreless innings in Grapefruit League action, Humber was given his first opportunity to start Tuesday. Humber had pitched mostly in the latter innings of ballgames, so the Twins felt a start would allow them to see what he could do against a group consisting of more Major League hitters.

And Humber didn't appear to do anything to sway the team's confidence in him. He pitched three innings against the Orioles on Tuesday, allowing two runs on five hits while striking out two.

Humber cruised through the first two innings of his start, carrying his scoreless streak into a 12th inning. That's when the right-hander found himself in a bit of a jam. He gave up three consecutive singles to load the bases with no outs in the third. He then struck Melvin Mora out before giving up a two-run single to Nick Markakis.

Still, Humber managed to get back-to-back groundball outs to finish the inning and kept the damage to just the two runs.

"It felt like that was probably the best stuff I've had so far this spring in terms of in games," Humber said after his start. "It was nice to be able to have three pitches going that I could throw over the plate. The only thing I can say that I can improve on next time is two-strike pitches, I just caught too much of the plate with a few of those."

Gardenhire said that he was pleased with what he saw from Humber, and that the team even thought about having him go out for a fourth inning. But a blister on Humber's non-pitching hand, plus a high pitch count in the third, kept the Twins from sending him back out.

The pitcher who replaced Humber in Tuesday's game made a strong statement himself. Just five days after he gave up three runs in three innings in his first spring start against the Orioles, Blackburn came in and delivered a better outing. He pitched two scoreless innings, allowing just two hits.

Like Humber and Blackburn, Perkins has also been mentioned as a possible starter. But Perkins' consideration as a possible starter seems to be more up in the air. The Twins have two distinct camps on whether the left-hander should be a starter or a reliever. But that Perkins pitched just one scoreless inning Tuesday seemed to hint that the club might be leaning toward a relief role.

Competing along with Humber, Blackburn and Perkins for a rotation spot is right-hander Kevin Slowey. Of the four, it appears Slowey might have the edge considering his experience at the Major League level last year and his improvement so far over the spring.

But with the team unsure of whether Baker or Liriano will be ready for the start of the season, there now appears to be more room for at least one of these arms to seize the opportunity to grab a spot in the rotation.

"I think all these guys sense that," Gardenhire said of the team potentially needing additional starters now. "I think they all know where we're at and what we're trying to do. And you know what? They're grabbing the ball and taking advantage of it."