Left-hander Henry Owens -- currently at Triple-A -- was not effective in his earlier stint with Boston this season. Roenis Elias -- the lefty who was acquired from the Mariners in December -- has had mixed result for Pawtucket.
"Yes, the candidate pool is going to be internal," Farrell said. "Clay, Elias, Joe Kelly, Henry Owens -- someone grab it."
Asked specifically about Elias, Farrell said: "Wouldn't rule him out. He's come off a couple of outings where he's thrown the ball very well. You see the strikeouts spike at Triple-A, and for a guy that's got the number of starts at the Major League level, you'd like to see him dominate that level, because that kind of coincides with the ability that he has. So he would certainly be a candidate for that start on the 18th and beyond."
With a fastball that frequents the upper 90s, it would stand to reason that Kelly could be a strong option in the bullpen, where the Red Sox have also struggled a little of late. For now, he will continue to try to prove he can start.
"He'll go down and start for now," Farrell said, "depending on who grabs that fifth spot and runs with it. He is a power arm, but if his presence in the bullpen would be considered and looked at as an upgrade, I don't think we would rule that out."
Buchholz threw a scoreless inning for the win in his first relief appearance since 2008, but he took the loss his second time out, giving up three hits and three earned runs over 3 1/3 innings.
President of baseball operations Dave Dombrowski will undoubtedly pursue all possibilities before the Aug. 1 non-waiver Trade Deadline, but it's doubtful any additions are imminent.
"But our staff, my job and our staff, we've got to get the most out of the guys here," Farrell said. "And we believe in them. I'll tell you, we sit here where we are today because we've got a very good group of young players. We've got some guys in our rotation that are pitching very well. Eddie [Rodriguez] coming back to us is a boost."