Following Tuesday's 4-2 loss to the Blue Jays, Boston manager John Farrell announced that Lester was scratched from tonight's start in the finale, and Brandon Workman will be recalled from Triple-A Pawtucket to pitch.
The Red Sox had no trade to announce, but there's a very real possibility Lester could be in his final hours with the only professional organization for which he's ever pitched.
"Yeah, Brandon Workman will start [tonight]," said Farrell. "In light of all the uncertainty surrounding Jon Lester, it's probably in everyone's best interests that he does not make that start, so Brandon will be recalled. There will be a corresponding move roster-wise at some point [today]."
Prior to Tuesday's game, Farrell had said Lester was still on track to pitch, though Workman was already lined up as a contingency.
By scratching Lester from his start, the Red Sox could increase the urgency of their suitors to sweeten their offer in advance of Thursday's Deadline.
Also, Lester becomes more attractive to a potential suitor if he can pitch immediately after a trade, rather than having to wait until Monday.
Numerous teams have talked to the Red Sox about Lester, and there was a lot of buzz about the Pirates on Tuesday. The Dodgers are another possible destination, though they've thus far been unwilling to part with the type of top prospects (Corey Seager, Joc Pederson) the Red Sox seek. The Marlins have also expressed interest, according to Jim Bowden of MLB Network radio.
Even American League East foes such as the Orioles and Blue Jays surfaced at one point, but both teams appeared to be out of the running as of Tuesday evening.
While Red Sox veterans were still hoping the lefty would stay, they were bracing for the possibility of his exit.
"Yeah, it's tough," said Dustin Pedroia, who came up with Lester through the farm system and has won a pair of World Series titles with him. "We're not teammates -- we're family. It's something you don't like going through. It makes you feel worse. We don't want to be in this position. I know a lot of guys feel that if you play up to your capability ... we should be adding instead of subtracting. Hopefully he's here."
"Lester is like a brother to me, you know what I'm saying?" David Ortiz said. "Pedey was right. We've been together for a long period of time, and it comes to the fact that all these trades and rumors are going around, it can get a little complicated. We'll see."
Even though Lester is in the final year of his contract, it would have seemed inconceivable even a month or two ago that he could be traded. But the 48-59 Red Sox have faded fast and are 12 games back in the AL East.
At the very least, the club figures it is best off trying to trade Lester now for a top prospect, and perhaps rekindling talks with him as a free agent in the offseason.
Lester said multiple times in recent days that he would still try to re-sign with Boston if the club traded him.
"It's surprising, but with this game, you never know. You never know what's next. We'll see," said Ortiz.
It was just last October that Lester's dominance played a large role in the Red Sox winning their third World Series in the span of a decade.
"Yeah, if we have a big game to play, we want him pitching it," Pedroia said. "I've seen him every start. It would be tough to see him in another uniform. I hope in a couple of days he's here, because it means a lot to me and everyone else and what he's done here. I'm hoping we open the door and he's in there."
Ian Browne is a reporter for MLB.com. Read his blog, Brownie Points, and follow him on Twitter @IanMBrowne. Steven Petrella is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.