The Red Sox also optioned outfielder Rusney Castillo to Pawtucket. They have two roster spots to fill before Saturday's game, but the club wasn't ready to make an announcement after Friday's loss.
It wound up being just a one-start stint on the rotation for Elias, as the Red Sox utilized a fifth starter for the first time since June 1.
Buchholz, who fired three scoreless innings with no walks and four strikeouts on Thursday, hopes to give the Red Sox the type of success they've lacked in the lower portion of the rotation all season.
"We didn't anticipate the number of guys we've gone through for 66 games," said Farrell. "We'll continue to search. Right now it's internal. Right now that would put Clay back in the rotation. That's the approach we're going to take, and hopefully he continues to build on the three innings he pitched [Thursday] night, which might be the most crisp he's thrown so far. That's the approach we're going with right now."
Buchholz was 2-5 with a 6.35 ERA in 10 starts before being moved to the bullpen. He was 1-1 with a 2.89 ERA in five relief appearances.
Ian Browne has covered the Red Sox for MLB.com since 2002. Follow him on Twitter @IanMBrowne and Facebook. This story was not subject to the approval of Major League Baseball or its clubs.