Rusch was not available to pitch on Tuesday, although he did plan to have treatment and do some light tossing.
Rusch said the injury did not feel as bad as the strained left groin he suffered during the 2003 season, which caused him to miss three weeks.
"I'll give it a day," he said. "It really was the right move to get me out of there, rather than going back out there and trying to tough my way through it."
"This isn't time to be a hero," he said.
Nomar returns: Nomar Garciaparra was back in the Cubs' starting lineup on Tuesday after taking a day off to regain his strength.
On Monday, Baker said the Cubs shortstop had been battling "allergies" and was feeling weak.
Garciaparra, who is batting just .182 with no homers and four RBIs, isn't convinced a day off was the way to go.
"I've felt sick for the past week," he said. "I still feel the same, but days off are not something I look forward to. (Baker) was going to give me a day at some point. He told me (Monday) was the day."
Garciaparra was particularly eager to keep playing and work his way out of an early season slump.
"My approach is always to play my way through it," he said.
Hard-luck Cubs: Baker figures the Cubs' luck is due to change, but he acknowledges that his club has had far too many games resembling Monday's come-from-ahead loss to the Reds.
Although it's still early, Baker still laments those losses.
"It's hard to take anytime," he said. "It's going to happen. It's good that it's happened early. You hate to have games get away when we've fought so hard to come back in or stay ahead of."
Still, Baker is proud of the way the Cubs have maintained their composure through all of the ups and downs of this young season.
"I commend our guys for playing 27 outs," he said. "I've seen a lot of teams get down, but not this team. You have to put those games behind you and move forward. There have been a lot of games where one hit or bounce could change the outcome."
Rival Redbirds: The Cubs travel to St. Louis after Tuesday night's game, where they'll begin a two-game series at Busch Stadium beginning Wednesday night. The Cubs were 8-11 against the Cardinals last season, including a 4-6 mark at Busch Stadium.
Baker says it's not just the Cubs who've struggled at St. Louis.
"Nobody has luck there," he said. "They're tough at home. We didn't have luck when I was with L.A., or San Francisco or any other team."
How far would a couple of wins at Busch Stadium go toward establishing the Cubs in the divisional race?
Not far, says Baker.
"Two games don't set a tone," he said. "There are too many games left to play."
Minor matters: Left-hander Renyel Pinto struck out 10 in five innings and David Kelton was 3-for-4 with a double, home run and three RBIs as the Iowa Cubs completed a three-game sweep of Albuquerque with a 7-6 victory Monday. ... Outfielder Matt Murton belted two home runs to help lead the West Tennessee Diamond Jaxx to an 8-6 win over Tennessee. ... Chris Walker was 2-for-4 with a triple and third baseman Scott Moore was also 2-for-4 with a double, but the Daytona Cubs lost, 10-2, to Jupiter. ... Ryan Harvey's three home runs led the Peoria Chiefs to a 10-5 win over Wisconsin. Harvey was 4-for-5 with the three homers and seven RBIs.
Up next: The Cubs face the rival Cardinals for the first time this season on Wednesday with Carlos Zambrano opposing Jeff Suppan in the first game of a two-game series at Busch Stadium. First pitch is set for 6:10 p.m. CT.