Red Sox general manager Theo Epstein also said the team had been discussing a contract extension for outfielder Jason Bay and made him an offer last week. Unable to reach a deal, the two sides agreed to shelve talks until after the season.
The 35-year-old Lowell, batting .282 with 10 home runs and 41 RBIs, has not played since June 27 because of a sore right hip. The 2007 World Series MVP missed last season's ALCS against Tampa Bay and had arthroscopic surgery on the hip last October. He also had an injection in his hip on June 29.
"I'm just really excited," Lowell said. "I feel good. This will be a nice first test, turf and everything. We'll see how it goes."
Manager Terry Francona said Lowell looked comfortable during a workout Thursday.
"He moved around really well last night, better than we've seen in a long time," Francona said.
The Red Sox have 10 days to trade or release Lugo, who signed a four-year, $36 million free agent contract with Boston before the 2007 season. If the team cannot trade him, it will have to absorb about $13 million over the next year and a half.
Epstein called Lugo's contract "a mistake" and "a lesson learned."
"Obviously we'd be bending the truth to say it worked out the way we envisioned," Epstein said. "He just never got on track here, never got locked in and comfortable and never played even close to the way we expected. When you dabble in free agency, sometimes these things happen."
Lugo was batting .284 with one homer and eight RBIs in 37 games and had made seven errors. While he didn't attend Thursday's mandatory workout, that's not why he was let go. Infielder Jed Lowrie is expected to return Saturday after having wrist surgery in April and will share time at shortstop and third base with Nick Green.
"We felt like those two would be our best combination," Epstein said.
Bay, batting .260 with 20 homers and 72 RBIs, is eligible for free agency at the end of the year. The Red Sox negotiated with Bay during spring training, then suspended talks after the season began before picking them up again in mid-June.
"It's now clear that this round of talks won't result in a deal, either," Epstein said. "We're going to table discussions again, once again as a mutual decision and pick them up, most likely, after the season.
"There's disappointment," he said. "Both sides want this to work. We were really hopeful with the aggressive offer that we made that we could have reached a deal now."
Bay said he is not committed to testing the free agent market and was willing to remain in Boston if the offer was right.
"I'm not really in the market, I'm not trying to set a precedent," the All-Star left fielder said. "I'm just looking for something that's fair."
Buchholz, 7-2 with a 2.36 ERA at Triple-A, made his first start for Boston since Aug. 20, 2008. He was demoted to Double-A Portland the following day. He pitched a no-hitter for Boston in 2007.