Rusch has already lost four times this season and has an 8.46 ERA through five starts. He has allowed a team-high 11 home runs, which almost doubles Carlos Zambrano's runner-up total of six.
Much had been made of Rusch's future in the rotation this season, especially of late with promising left-hander Rich Hill having gotten off to another blazing start for the second straight season in the minor leagues.
On Sunday, Baker was asked about Rusch's struggles and whether he'd had a chance to discuss them and his future in the rotation with pitching coach Larry Rothschild.
"Yeah, but I'm not at liberty to discuss what we're going to do without talking to Glendon about whether we're going to do anything," Baker said.
"We'll let you know in the next couple of days."
"Well, conceptually, sometimes you don't have a choice," Baker said. "It depends on how good the three rookies are. We already have two in the lineup, and they're doing pretty good. Your hope is that they don't act like rookies. You don't mind having rookies, but you'd like rookies who don't act like they're rookies. That's what you want."
But the longer Rusch stays in the rotation, the longer the Cubs' bullpen risks being overtaxed. The veteran southpaw has averaged less than four and a half innings per start with three outings of less than five innings.
With right-hander David Aardsma struggling with a plus-10 ERA in four relief appearances, the Cubs had an easy decision to make on who to send down to make room for the addition of Hill.
Aardsma was in good spirits following the demotion.
"I made some pitches that I shouldn't have made," he said. "I'll work on being a little smarter [in Triple-A]."
For his part, Hill was scheduled to start Iowa's series opener with Nashville Monday night in the Music City, but has instead been promoted to Chicago, Iowa pitching coach Alan Dunn confirmed.
"Rich was throwing the ball well in his starts obviously," Dunn told Inside The Ivy. "I think he really built off last season and what he accomplished between West Tennessee and Iowa. The experience he got last year in the big leagues is only going to help him this time around.
"He'd done a good job of giving us quality starts and throwing the ball in the strike zone every time out."
Indeed, Hill got off to a blazing start last year at Double-A before being called up to Chicago in June. He struggled with the big league club last season in 10 appearances and four starts.
Earlier this spring, after he was optioned to Iowa and Marshall was given the Cubs' fourth spot in the rotation, Hill implied that he felt a strong full season between Double-A and Triple-A (which included an 11-4 record, a 3.32 ERA and 194 strikeouts to 35 walks last year) was a better judge of performance than anything put together in Spring Training.
"It's frustrating to have to go back and prove myself again at Triple-A," Hill said at the time. "Things happen for a reason. Hopefully, I'll go down there, pitch well and get [to Chicago] as soon as possible."
And Hill has proven himself -- at least for the time being. He was 1-0 with a 1.44 ERA and 33 strikeouts to seven walks in four starts at Triple-A and had four straight quality starts. He was second in the Pacific Coast League in both strikeouts and ERA.
The Cubs finished April with a winning 13-10 record, but are tied with Milwaukee for fourth place after the Brewers embarrassed the Cubs over the weekend by outscoring the team 25-2 in the series' final two games.
Baker was asked if he would have taken a 13-10 record for the first month when considering the injuries to the Cubs' rotation and to first baseman Derrek Lee.
"No, I don't think like that. I always think we can do better," said Baker, looking like the cat that just swallowed the canary. "I always think I can do better and everybody can do better. That's part of my job. You have to accept where you are, because you have no choice.
"Acceptance is one of the toughest things in life, but I'd be happy with a couple of more wins."
A rotation without Glendon Rusch can only help.