OAKLAND, CALIF. - The Twins not only sent righthander Nick Blackburn to Class AAA Rochester on Monday, they outrighted him off their 40-man roster. And the club didn't stop there, as they also outrighted embattled infielder Tsuyoshi Nishioka.

They are the latest moves of an organization in the middle of a second straight disastrous season.

In order to a player to be outrighted off the 40-man roster, that player has to clear waivers. So every club passed on Blackburn and Nishioka. That's not surprising, but still a reflection of how this year has gone. As Twins assistant general manager Rob Antony pointed out, "When you're taken off the major league roster and 29 other clubs pass on you, it tells you you're not doing very well."

Unless they are put back on the 40-man roster, neither Blackburn nor Nishioka will be eligible to return to the Twins when minor league seasons wind down and major league rosters expand Sept. 1. However, Antony told Blackburn that if he pitched well enough with the Red Wings, he could be returned to the 40-man roster in September and called up.

"I talked to Nick [Monday] to let him know and told him, 'Go down there, try and get straightened out and when September comes we'll evaluate the situation.' There's no guarantees he'll come back," Antony said. "We could select him and bring him back if we want, or he could not be back this year -- whatever we think is the right situation when the time comes."

As of now, no one from the projected Twins rotation on Opening Day -- Blackburn, Carl Pavano (60-day DL), Scott Baker (60-day DL), Francisco Liriano (traded) and Jason Marquis (released) -- are on the 40-man roster.

Blackburn, 30, is 4-9 with a 7.39 ERA in 19 starts, and it's his third consecutive losing season. He was 22-22 with a 4.04 ERA over his first two full years, decent numbers for an end-of-the rotation starter. Since then, he's 21-31 with a 5.56 ERA.

He entered the season coming off a strong spring training (2.12 ERA) but struggled early. He had a bizarre run in April when his shoulder cramped up during a game, then there was unexplained soreness in his rib cage area. Finally, a sore left quad landed him on the disabled list in May.

When he returned, he couldn't keep the ball down and suffered the consequences, often putting the Twins in early deficits.

"A couple of injuries and he never really recovered from it coming back," manager Ron Gardenhire said. "He didn't really have the same sinker. He had a couple ballgames where the ball sunk down pretty good. And it looked like he was finding his way. But he's been inconsistent."

Scheduled to make $5.5 million in 2013 in the final year of a four-year, $14 million contract, Blackburn probably will be back next year to fight for a spot in the starting rotation.

The Twins will announce on Tuesday who will be added to the major league roster to replace Blackburn and start on Wednesday at Oakland, but indications are that righthander Liam Hendricks is the leading candidate at Rochester.

Nishioka came to the Twins last season in a splashy, three-year, $9.25 million deal -- in addition to a $5.3 million posting fee -- as the answer at short.

His play has forced the Twins to draw a different conclusion.

After batting .226 and breaking his left leg last season, Nishioka didn't have a shot to make the club out of spring training. But, based on reports that his play had improved, the Twins called him up and played him in three games in Cleveland two weeks ago.

His sacrifice fly helped the Twins win on Aug. 7. Other than that, Nishioka was 0-for-12 and a disaster in the field.

Nishioka appears to be one step from having his contract bought out, or sold, and his ties with the Twins severed as he is one of the worst acquisitions the club has ever made.

"We'll discuss all that after the season's over," Antony said. "I can honestly say we have not talked about any of that right now. We're trying to get him better. He had been playing better and they said now was as good a time as any to give him a shot; we gave him a shot and it just didn't work out."