The Jon Lester talks have entered the final turn, with an expectation that a choice will be made no later than Tuesday, according to sources involved in the negotiations.
The options have dwindled by one, as San Francisco Giants general manager Brian Sabean confirmed Tuesday night that his organization had been told Lester would sign elsewhere.
The Cubs had no comment Monday.
Red Sox GM Ben Cherington indirectly acknowledged that Lester could elect to go elsewhere.
"We need to build a rotation and we need to be in on all sorts of stuff and we have been in on all sorts of stuff," Cherington said late Monday. "There are probably 15 to 20 starting pitching scenarios we've talked about and worked on. Not all of those are going to land; more won't than will. But we're working as hard as we can. We're going to build a good rotation."
Once Lester has a general agreement in place with a team, there will be other issues to resolve before there is a formal announcement, from a medical review to a physical examination.
Red Sox principal owner John W. Henry flew to the Atlanta area Friday for a one-on-one meeting with the former Boston left-hander, WEEI.com reported Saturday, citing multiple major league sources.
Henry and other members of Red Sox ownership had previously met with Lester during the free-agent process, the website reported.
Lester, 30, went 6-4 with a 2.35 ERA for the Oakland Athletics after he was acquired in a blockbuster trade-deadline deal with the Red Sox in exchange for outfielder Yoenis Cespedes. Overall, he was 16-11 with a career-best 2.45 ERA in 2014.
He was on the hill for the A's in the American League wild-card game against the Kansas City Royals and left in the eighth inning with runners on first and second with one out and his team leading 7-4. The Royals eventually won the game 9-8 in 12 innings.
Lester is noted for his performance in the postseason, where he has a 6-4 record and 2.57 ERA in 14 appearances. He has been dominant in the World Series, where he is 3-0 with a 0.43 ERA in three starts, helping the Red Sox win two championships.
Lester, who has a career mark of 116-67 with a 3.58 ERA in nine seasons, rejected a four-year, $70 million contract extension offer from the Red Sox in the spring. He was paid $13 million last season.
ESPNBoston.com's Gordon Edes contributed to this report.