That "just in case" came on Wednesday, when the lefty reliever was added to the Red Sox's roster.
It marked the second Major League stint of the season for Jones, who was with the Red Sox from April 15-May 21.
Why is he reentering the mix now? Part of the reason is that Junichi Tazawa, another September callup, was placed on the 60-day disabled list on Monday with a tender left groin.
"He's going to be an added bullpen arm, just because I think last night, we felt like we got into a little bit of an area that we didn't want to get into," said Red Sox manager Terry Francona. "There's a lot of roster issues we were battling this week. We kind of got through that. I guess we all kind of felt like, 'OK, if we ran into a problem with rain or a line drive, that if we didn't have another arm, shame on us.'
"They had told him the last day of the season that this could happen so keep throwing. He is another guy who can maybe give us two innings if we have a game like that just to save somebody else."
Regardless of the circumstances, Jones was pleased to be back.
"It was nice," said Jones. "It was kind of a shock, you know?"
In his initial stint with the team, Jones posted an 8.00 ERA in eight outings.
What did he learn from that?
"A lot of things," said Jones. "I feel like I learned how to throw my offspeed stuff for strikes a lot better and just how the ballclub reacts to everything -- and just how focused this team is on winning."
Jones made 36 appearances at Pawtucket this season, going 4-3 with a 4.25 ERA.
Ian Browne is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.