Justin Masterson couldn't get out of the third inning on Tuesday night. The right-hander surrendered six earned runs on six hits and one walk in 2 1/3 innings and now rumors are swirling in regards to his status as a starter.

In Masterson's defense, he isn't the only problem that has engulfed Boston's pitching staff, but his drastic velocity decline has significantly handicapped his ability to gain an advantage against opposing hitters, and it has shown. The 30-year-old is 2-2 with a 6.37 ERA and 1.67 WHIP in seven starts (35 1/3 innings).

Last night marked his worst outing of the season. He threw only 57 pitches before manager John Farrell took him out of the game. Masterson has only three quality starts this season, but the team has managed to only get him one win in those outings while losing the other two. The Red Sox knew replacing pitching coach Juan Nieves with Carl Willis wasn't going to work magic, so personnel changes could come sooner rather than later.

"One option would be put Masterson on the disabled list with an injury," writes Peter Abraham of the Boston Globe. "He has had shoulder issues in the past and that would fit the ball. The Sox have a history of putting pitchers on the DL with what amount to sprained ERAs.

"The other option, less likely, would be to shift Masterson to the bullpen. But his value there would be negligible at this point. Serving as a long reliever is not likely to solve his issues.

"A far lesser outcome would be to release Masterson or designate him for assignment. He was signed to a $9.5 million deal and the Sox will exhaust all avenues to get something more from him before resorting to that."

The Red Sox fell to 15-18 with last night's loss to the A's and the starting rotation is largely responsible for the team's struggles. Boston's offense carried the club in April, but the scoring has slowed down in the month of May, resulting in a 3-8 record. The pitching staff owns a 5.05 ERA in those games. The starting rotation is 2-7 with a 6.08 ERA.

It's unknown what's next for Masterson, but Farrell's comments after the game weren't promising for the right-hander moving forward.

"Clearly he's not right," Farrell told Abraham. "Whether that's physical, whether that's delivery-wise, the ball's not coming out of his hand as he's shown for the better part of this year. We've got to gather some information overnight."

Masterson is slated to start on Sunday against the Seattle Mariners, but the Red Sox could make a change before then.

UPDATE: Justin Masterson has been placed on the disabled list, according to Craig Calcaterra of NBC Sports' HardballTalk.