BOSTON -- With Kevin Youkilis out of the starting lineup for the third straight game with a sore back, the Red Sox have brought in reinforcements. What happens next remains to be seen.

Shortstop Jose Iglesias was recalled from Triple-A Pawtucket prior to Tuesday night’s game against Oakland.

Manager Bobby Valentine said that he does not know if Youkilis will need to be placed on the disabled list. But in the short term, Valentine did not want to be left out in the cold if he needed some help on the left side of the infield.

“With the playing conditions and with the roster situation, I didn’t think it was fair to the team to play so short in the infield, so we have a backup in case we need it,” Valentine said.

Reliever Junichi Tazawa was optioned to Pawtucket to make room for Iglesias on the roster. However, intrigue will surround the situation as the statuses of Youkilis and of right-hander Aaron Cook hang in the balance.

Cook has an opt-out clause in his contract if he is not added to the major-league roster by Tuesday. With Tazawa back in Pawtucket, a spot would seem to be available for Cook as the club is carrying just 11 pitchers. A Cook-for-Iglesias swap would make sense. Of course, that is all predicated on the recovery of Youkilis, a timeline that remains fuzzy at best.

“I was with him today in the training room and there’s times where it’s pretty sore, different movements,” Valentine said of Youkilis. “He’s doing everything he can in that training room. Yesterday it was during infield practice, the day before it was during batting practice. He’s doing everything he can. Other [medical] opinions or any of that stuff, I’m not sure where we are on any of it.

“It seems like he has a situation we just have to get over.”

When asked if the DL is a possibility for Youkilis, Valentine said, “I can’t tell.”

In his afternoon session with the media, Valentine added that “there is no news” on Cook. Yet.

Igelsias hit .200 (17-for-85) with just one extra-base hit, a double, in 22 games for the PawSox. He could be a defensive replacement during his time in Boston, or perhaps start at shortstop with regular shortstop Mike Aviles moving to third base.

Veteran Nick Punto was at third for the third straight time Tuesday. He was 0-for-6 with four strikeouts in his first two starts in place of Youkilis.

Tazawa has thrown 6 1/3 scoreless innings of relief for the Red Sox, allowing five hits and striking out four. Valentine insisted that Tazawa’s option was purely a product of the roster situation and not based on the righty’s performance.

Here's the Red Sox lineup for tonight's game:

1. Mike Aviles, SS

2. Ryan Sweeney, RF

3. Dustin Pedroia, 2B

4. Adrian Gonzalez, 1B

5. David Ortiz, DH

6. Cody Ross, LF

7. Jarrod Saltalamacchia, C

8. Marlon Byrd, CF

9. Nick Punto, 3B

Felix Doubront, LHP