Baltimore replaces Reimold, who was batting .205 with two homers and 10 RBIs in 29 games, with Patterson, who went 1-for-5 with a run scored while leading off and playing left field Wednesday night. The 30-year-old Patterson is beginning his second tour of duty with the Orioles.
Trembley said Roberts became involved in the transaction when the second baseman spoke with president of baseball operations Andy MacPhail on Tuesday and reported no progress in his recovery. Roberts has yet to resume baseball activities and there is no timetable established for his return.
"Thirty days have already gone by," Trembley said. "Andy had a conversation with Brian yesterday to find out where he was at, and it was decided that he is going to need at least another 30 days. So we needed a roster spot, so that's why that decision was made."
Asked when he expected Roberts back in action, Trembley added: "I have gone by the premise that was given to me earlier that it wasn't days, it was weeks. So I have stayed along those lines in thinking that is where we were at. I know Brian did relay that he feels that he wants to start upping his activities in the next few days. I hope that is the case, because obviously it would be our benefit to get him back here as soon as we can. But we want to get him back here when he is 100 percent."
News of Reimold's demotion caught his teammates by surprise, even though Patterson's name was written into the lineup posted in the clubhouse before Wednesday's game.
"It's crazy that he's the one that moved," center fielder Adam Jones said. "He's just got to go down there and rake Triple-A pitching -- act like he doesn't even belong there, because he doesn't. [He needs to] come back up here with a new mentality and start back over."
Patterson, who was signed by the Orioles to a Minor League contract April 21, opted out of his deal with the Mariners at the end of Spring Training, when it became evident he wouldn't break camp with them. He re-signed with Baltimore on a Minor League deal and was assigned to Norfolk, where he batted .368 (21-for-57), hitting safely in 12 of 14 games and recording an 11-game hitting streak. Patterson played 267 games for the Orioles in 2006-07 after being acquired from the Chicago Cubs.
"You always feel, I guess in general, you leave organizations [and] no way you're going to be back," Patterson said. "It happens occasionally. But I'm happy to be back here, I look forward to helping the team, contribute to some wins. There's obviously work to do, but I'm looking forward to that."
Hitting leadoff may be Patterson's role now, but he isn't married to any batting position.
"I think people tend to make a big deal a little too much about certain spots in the lineup. You still have to have the same objective, and that's to get your pitch right where you want it and try to put a good swing on it, and if it's not there, lay off," he said. "Where you bat in the lineup, for me, can be a little overrated at times."
Trembley viewed the move as a necessity, given the depth of Reimold's growing frustration at the plate.
"We sent Nolan out and brought in Patterson here and hope it helps the club and helps Nolan. I hope it is a two-fold purpose here," Trembley said. "We need to get somebody that can spark our offense -- I am not putting it all on Corey, but he has been a leadoff guy in the past. He was playing very well at Triple-A. Nolan wasn't playing well here. It's unfortunate that these things happen, but they do happen."