The Cubs did not say when or where Doubront would report, and manager Rick Renteria said he was not that familiar with the lefty. Doubront was unhappy in Boston because he wanted a chance to start.
"The thing is, if the [Red Sox] say I have to prove myself, I already did, man," Doubront told Boston media on Sunday. "It's [messed up]. So if these guys say I have to pitch to prove whatever, no, they already know what I have. I showed them what I have as a reliever and as a starter. For me, they don't see the numbers, they don't care what I've done in the past. It's hard to be happy like that with these guys."
Will a new team help Doubront?
"I don't necessarily buy into the chance of scenery," Red Sox manager John Farrell told the media in Boston on Wednesday. "Can it invigorate someone in a new surrounding? But as I talked with him a little bit a while ago, if this [trade] does come to fruition, the work is always going to be needed, regardless of where you pitch or the role in which you're pitching in.
"He has performed well for us over a period of time, and it can't be understated the importance of his relief appearances last year in the World Series," Farrell said. "Those were two pivotal outings by him, and he did a great job."
Doubront appeared in two games in the League Championship Series and two World Series games, and gave up one earned run over seven innings.
Farrell said the problem with Doubront was a lack of consistency.
"When you talk about any pitcher, not just in this situation, consistency is driven from a number of ways," Farrell told reporters. "Every player has maintenance in their work routine. In a pitcher's case, his delivery to repeat, to consistently throw strikes, to be aware of game situations.
"I can't say that there was one thing that caused him [problems]. ... He did suffer from the one fatigue outing where he spent some time on the [disabled list] after that," Farrell said. "But he seemed to never get on a roll like he did last year, where it was 15, 16 straight starts of three runs or less. That was missing this year."
On Monday, Doubront gave up six runs on six hits and two walks in two-thirds of an inning against the Blue Jays. After the outing, the lefty was asked if he was "disinterested."
"I don't know that two nights ago triggered a trade," Farrell told reporters in Boston. "I don't think any trade just happens overnight. I wouldn't say it's a direct result of that."
Doubront will be eligible for arbitration in 2015 and won't be a free agent until 2018.