BOSTON — Just like that, the Boston Red Sox have a starting rotation again.

With two deals announced on Thursday and a third coming soon, the Red Sox have rebuilt their starting rotation this offseason almost as quickly as they took it apart during the summer. Hours after trading for Detroit right-hander Rick Porcello, Boston signed righty Justin Masterson as a free agent.

A deal with Arizona for lefty Wade Miley was announced Friday night. Right-handers Rubby De La Rosa and Allen Webster and infielder Raymel Flores went to the Diamondbacks.

“Once we got closer on those opportunities, we just felt like they all made sense,” Red Sox general manager Ben Cherington said during a conference call on Friday. “We’re very happy with Justin here, and obviously, Porcello. And hopefully we’re getting closer to another one, too.”

The Red Sox won the World Series in 2013 with a rotation that included Jon Lester, John Lackey, Jake Peavy and Felix Doubront. But when it became obvious the team would not successfully defend its title in ”˜14, Cherington traded them all away to start planning for the future.

Lester, who spent his entire career in the Red Sox organization until he was shipped to Oakland at the trading deadline, was courted to return as a free agent. But when the Chicago Cubs outbid Boston for the 31-year-old lefty, Cherington quickly executed a backup plan.

Now, Masterson, Porcello and Miley will join holdover Clay Buchholz and one of Boston’s young arms ”“ perhaps Anthony Ranaudo or Brandon Workman ”“ in a rotation that is so far lacking an ace.

Masterson isn’t sure they need one.

“I think we have an incredible staff. We’ve all had a bit of success, and I think … we’ll continue to do that,” he said on the call. “The ace category is always more of a fan-media type of thing. Usually there’s a leader. The starting pitcher is the ace of that day. That’s the biggest thing: a guy understanding that he has to go out there and do his job.”

Masterson came up in the Red Sox system and spent part of two seasons in Boston before he was traded to Cleveland. He spent four more seasons there before he was sent to the St. Louis Cardinals this summer at the trading deadline.

Although he has a 60-72 career record and a 4.24 ERA, Cherington said he was one of the best pitchers in the AL in 2011 and 2013. This season, he had a 5.88 ERA and spent time on the disabled list with right knee inflammation.

“We’re very confident that whatever physical issues affected him in 2014 will be behind him,” Cherington said.

Cherington confirmed that Masterson, who bounced in and out of the bullpen during his first Boston stint, is slotted for the rotation this time around.

But the pitcher said he knew that was something less than a guarantee.

“The assurance was that if I pitch the way I’m supposed to, I will be a starter,” he said. “If I’m not, the decision will be made. And I won’t be happy anyway.”

NOTES: In a separate trade Friday, Boston obtained Zeke Spruill from the Diamondbacks for Myles Smith in a swap of right-handers.