OAKLAND -- The Twins received good reports on rehab starts from right-handers P.J. Walters and Kyle Gibson, who both pitched in the Minors on Sunday.

Walters, on the disabled list since June 14 with right shoulder inflammation, tossed three scoreless innings for Triple-A Rochester. He struck out six and walked two while throwing 59 pitches.

"He was fine," Twins assistant general manager Rob Antony said. "He felt good, everything's fine there."

Gibson, meanwhile, made his second rehab start with Class A Advanced Fort Myers. The right-hander, who is coming off Tommy John surgery last September, gave up just one run on three hits over four innings.

He's now pitched in nine games in the Minors this season, posting a 2.49 ERA with 23 strikeouts and five walks in 21 2/3 innings.

Right-hander Carl Pavano was scheduled to make a rehab start with Fort Myers on Tuesday, but will instead meet with Dr. David Altchek in New York. Pavano, on the disabled list since June 4 with right rotator cuff weakness, has been conferring with Altchek, but wanted to meet with him in person.

Antony, though, said that Pavano hasn't suffered a setback and that it was the only day Althcek could meet with Pavano. He's expected to make another rehab start in a few days.

Blackburn outrighted to Triple-A Rochester

CWS@MIN: Blackburn tosses eight strong vs. White Sox

OAKLAND -- The Twins outrighted struggling right-hander Nick Blackburn to Triple-A Rochester, and will recall a starting pitcher on Tuesday to start on Wednesday against the A's. In addition, Minnesota also outrighted infielder Tsuyoshi Nishioka, who will remain on the Rochester roster.

Blackburn was removed from the 40-man roster after having a rough time with the Twins, posting a 7.39 ERA in 19 outings. His last start came Friday, when he gave up five runs on 11 hits over 5 1/3 innings.

He'll be a starter in Rochester, and Twins assistant general manager Rob Antony said Blackburn will have to pitch well to be back up with the club again this season, as he's no longer on the 40-man roster.

"I talked to Nick today, let him know and told him, 'Go down there, try and get straightened out and when September comes, we'll evaluate the situation,'" Antony said. "There's no guarantees he'll come back. 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."

Blackburn is still owed $5.5 million next season, and will have to earn a spot with the club, according to Antony.

"As far as next year goes, he's still a member of our organization," Antony said. "I suspect, unless we trade him in the offseason, he'll be back in Spring Training trying to win a job on the club."

With Blackburn out, the Twins need a starter for Wednesday, and it's expected to be right-hander Liam Hendriks, who last pitched for Rochester on Friday. The 23-year-old has been impressive with the Red Wings with a 2.20 ERA in 16 starts, but it hasn't translated with the Twins, as evidenced by his career 6.71 ERA in 12 outings.

Nishioka, who is also owed $3 million next year, struggled in three games with the Twins this year, going 0-for-12 with two errors and several other misplays in the field.

"I'm sure it's a pride thing for any player," Antony said. "No. 1, it's tough to be in the Minor Leagues; but No. 2, 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."

The team now has 38 players on its 40-man roster.

Span undergoes MRI, sits for seventh straight game

OAKLAND -- Center fielder Denard Span underwent an MRI exam on his neck on Monday, and was again held out of the lineup for a seventh straight game on Monday against the A's.

Span, who is scheduled to have another MRI exam on his right clavicle on Tuesday, originally hurt his shoulder landing awkwardly while trying to make a diving catch on Aug. 12. The MRI on his neck came back clean.

"He couldn't get through both of them today," assistant general manager Rob Antony said of the MRI exams. "Basically we're doing that just to make sure we're not missing anything. We want to rule everything out and give him peace of mind."

With Span out, Ben Revere started in center field with Darin Mastroianni getting the start in right field.