Jackson, the highly touted outfielder who was the Cubs' No. 1 pick in 2009, will stay at Triple-A Iowa for now, Cubs general manager Jed Hoyer said. In 15 games, Jackson was batting .242 with two homers, five doubles, two triples, two stolen bases and eight RBIs.
"Brett's playing hard, and all the reports on what he's doing in Iowa are good," Hoyer said. "He's still early in his Triple-A career. He hasn't had that many plate appearances down there. He still has work to do.
"We feel he's a big part of our future, but I wouldn't read into anything as far as timing."
The Cubs added outfielder Tony Campana to the roster on Saturday when they placed pitcher Ryan Dempster on the disabled list and will use him in center as well as Reed Johnson and Joe Mather.
Byrd, 34, was hitting just .070 over his first 43 at-bats. He did not play Saturday in the Cubs' 6-1 win over the Reds.
"The slow start didn't play any part at all. We had talked about a deal [with the Red Sox] at the end of Spring Training. Our feeling was we've been trying to acquire relief pitching since the end of the winter. We felt like an area we have some surplus with young players we want to play is in the outfield, so that was a big part of it.
"The slow start, a lot of guys have a bad 45-, 50-plate-appearance stretch," Hoyer said. "We wouldn't be doing our job well if we let that play into it. We felt we had some guys who can be a big part of our future. Realistically, Marlon was in the last year of his deal, and we felt we wanted to give some plate appearances to other guys."
The Cubs, who are already paying a large part of Carlos Zambrano's contract since he was traded to the Marlins, will cover a significant portion of Byrd's $6.5 million salary for 2012. It's the final year of a three-year, $15 million contract.
Bowden, 25, also got off to a slow start, but Hoyer, Theo Epstein, the Cubs' president of baseball operations, and scouting and player development director Jason McLeod know the pitcher well. They selected him in the supplemental round of the 2005 First-Year Player Draft with the Red Sox.
The right-hander began the 2012 season on the Red Sox's Opening Day roster, giving up one earned run over three innings in two relief appearances before he was designated for assignment on April 15. Bowden has a 3.91 ERA in 16 Major League appearances since the start of 2011.
"Michael's a guy we've known since 2005," Hoyer said. "He has tremendous makeup, a very hard worker. He's also a local kid and is excited about being with the Cubs. The relationship helps when you know a guys makeup and how hard he works. That's nice when you make a trade."
Bowden is a 2005 graduate of Waubonsie Valley High School in Aurora, Ill. Last year, he reached Major League highs in several categories, including 14 appearances (tied with 2010), 17 strikeouts, 20 innings pitched and nine games finished.
Bowden is expected to join the Cubs on Monday in Chicago. The Cubs have a list of players to choose from for the player to be named, and Hoyer said he expected a decision to be made by mid-May. It will most likely be a pitcher, he said.
The Red Sox have been exploring the trade market since center fielder Jacoby Ellsbury suffered a partially dislocated right shoulder on April 13 while trying to break up an inning-ending double play and landed on the disabled list. Boston is also missing left fielder Carl Crawford, who started the season on the 15-day DL while recovering from offseason left wrist surgery.
Byrd hit .293 with 12 homers and 66 RBIs that first season in Chicago, earning the only All-Star Game berth of his 11-year career. Last season, he hit .276 but was limited to 119 games because of an injury, which he suffered at Fenway Park when Byrd was hit in the face by a pitch by Boston's Alfredo Aceves.
"You know, he's been a good Major League center fielder for a long time and he's off to a tough start, but our hope is that a change of scenery, maybe a new environment, we can get him going and help us," Red Sox general manager Ben Cherington said Saturday.
The Ellsbury injury motivated them to make a move. Byrd handled the news well.
"I think he's excited to have the opportunity in Boston, knowing they've had some injuries and there will be playing time," Hoyer said. "You're on a big stage in Chicago and he's going to be on a big stage in Boston, and I think he relishes that.
"Obviously, he's been in a little bit of a funk and sort of having the batting average reset and going to the American League might be a good thing for him."
Carrie Muskat is a reporter for MLB.com. She writes a blog, Muskat Ramblings, and you can follow her on Twitter@CarrieMuskat. This story was not subject to the approval of Major League Baseball or its clubs.