"Eduardo will go 75 pitches tomorrow, and then provided he gets through that as anticipated, we'll look to get him out to an affiliate to advance his progression," Farrell said. "It still remains to be seen where he'll go.
"Carson came through yesterday in very good shape, with his normal velocity. He's going to throw another inning tomorrow before he'll go out and join an affiliate."
Smith has yet to make his Boston debut after the team acquired him in the Wade Miley deal during the offseason. The righty reliever has been a lockdown arm, but he got hurt in a Grapefruit League game vs. the Cardinals on March 20.
"Most importantly, he's feeling strong and the action to his pitches is regaining his normal form," Farrell said.
The team wants to see Smith throw in a back-to-back situation, even if one of the outings is abbreviated. Farrell said there are still a "couple checkpoints" to clear and the Sox can't afford to rush him back.
"Anytime we look to skip steps and not take the appropriate time, it's not good," Farrell said. "If we're talking about a difference of two or three days at most, in the bigger picture, we have to be respectful of that and make sure his health is first and foremost."
As for Rodriguez, he will need a minimum of two starts, and his likely return date would be early May.
The southpaw was 10-6 with a 3.85 ERA and had 98 strikeouts to just 37 walks to fill out Boston's rotation nicely last season. He suffered the knee injury very early in Spring Training and has just begun to put his full weight behind pitches again.
"Tomorrow will tell us a lot about what he's ready for," Farrell said. "That'll give us more information and ... he won't be [limited for assignment location] by weather, because we're not talking about an arm issue.
"Both guys are advancing well. They're responding to the intensity ramping up, so their date of arrival is making headway."
Chris Abshire is a contributor to MLB.com based in Houston. This story was not subject to the approval of Major League Baseball or its clubs.