CHICAGO -- Cubs left fielder Alfonso Soriano left Monday's game in the first inning with a strained left quadriceps and underwent an MRI to determine the severity of the injury. The Cubs did not expect results until Tuesday.

Soriano grabbed his left leg a few steps from first base as he ran down the line on a groundout against Houston's Aneury Rodriguez to end the inning. Assistant athletic trainer Ed Halbur escorted Soriano off the field, and Blake DeWitt took over in left.

"It's unfortunate to see Sori go down like that," DeWitt said. "I haven't heard anything, but hopefully he's all right. He's a big part of this team. It's a tough loss today."

The Cubs have dealt with multiple injuries lately. They placed Jeff Baker on the disabled list earlier Monday, and he joined Reed Johnson (back), Marlon Byrd (face), Andrew Cashner (shoulder) and Matt Garza (elbow) on the DL.

DeWitt, who has never played the outfield in the big leagues until this year, went 3-for-4, including an RBI triple in the third in the Cubs' 12-7 loss to the Astros. He will get the bulk of playing time unless the Cubs tap into the farm system again.

"I'll give him a shot," Cubs manager Mike Quade said. "I know he slips and falls on the one ball, but he throws the guy out at the plate [in the seventh] and gets three hits. I'd like to keep his bat in the lineup. He's worked hard in left field. Why not?"

Quade said he could always insert a more experienced outfielder later in the game for DeWitt.

"At this point, we need his bat in the lineup," Quade said of DeWitt, who was hitting .280.

The Cubs have already called up outfielders Brad Snyder and Lou Montanez from Triple-A Iowa. Among the other options are Tyler Colvin, who began the year with the big league team but was sent down to Iowa after batting .113 in 28 games. He was hitting .260 in 12 games at Iowa with five doubles, two triples and one home run. Another choice may be Brett Jackson, the team's No. 1 Draft pick in 2009, who just rejoined Double-A Tennessee after being sidelined with a finger injury. Jackson was batting .295 in 32 games before he was hurt May 11.

Soriano was batting .271 and leading the Cubs with 12 home runs and 29 RBIs.

"[Injuries] are part of this game," DeWitt said. "It's a long year. Every team is going to battle through injuries. Good teams will push through it, and that's what we'll continue to do."

Garza could return to Cubs' rotation Sunday

CHICAGO -- Matt Garza, who has been sidelined since May 17 with tightness in his right elbow, threw on flat ground and played long toss Monday and could return to the rotation Sunday in St. Louis.

"[I] heard it was good," Cubs manager Mike Quade said of Garza's throwing session. "I heard it was real good. Great piece of news today."

The right-hander won't throw Tuesday, but he will get back on the mound Wednesday for the first time since the injury.

"That will be a big day to see how he does," Quade said.

The Cubs might want Garza to throw two side sessions before returning, Quade said, but if Wednesday's goes well enough, Garza could pitch Sunday against the Cardinals.

"Not out of the question," Quade said. "We'll keep our options open. I'd like him back as quick as I can get him back, but not so quick that I screw this thing up and we get him back too soon."

Cubs call up LeMahieu; Baker placed on DL

CHICAGO -- DJ LeMahieu got a call Sunday from Brian Harper, his manager at Double-A Tennessee, saying he was being promoted to Triple-A Iowa. Two hours later, he was fishing on a lake in Tennessee with a couple buddies when he got another call.

This time it was Oneri Fleita, the Cubs' director of player development, who told him there was a change of plans.

"I was like, 'Did I get traded?'" LeMahieu said. "[Fleita] said, 'Have you ever heard of Wrigley Field?'"

On Monday, LeMahieu was taking batting practice at Wrigley after being called up to replace Jeff Baker, who was placed on the 15-day disabled list retroactive to Sunday with a strained groin. Baker injured his groin May 22 in Boston, and shortly after watching him run gingerly to first base on a pinch-hit groundout on Saturday, Cubs manager Mike Quade decided the move had to be made.

LeMahieu, the Cubs' second-round Draft pick in 2009, was batting .358 with 15 doubles, two triples, two homers and 27 RBIs in 50 games with Double-A Tennessee.

"The first thing we've got to do is figure out how to spell his name," Quade joked.

LeMahieu's name is pronounced La-May-Hugh.

The Michigan native said his mother flew from California to Chicago, and his father and grandparents drove from Milwaukee to see him in a big league uniform for the first time.

LeMahieu played on LSU's College World Series championship team in 2009. He was LSU's starting shortstop as a freshman, but he has played second and third at Double-A. In May, LeMahieu was hitting .419 with 10 doubles and 16 RBIs in 27 games.

"[He] was red-hot in Double-A," Quade said. "[I] got a look at him in Spring Training -- nice looking player. [He] gives us a right-handed bat and some pretty good defensive versatility with he and Blake [DeWitt] now. We were looking for a guy that can fill in at second and third, even short if need be."

LeMahieu, 22, hit a walk-off homer for the Cubs in Spring Training. Right now, though, he's not a power hitter.

"He's a big kid, and you'd like to think he'll grow into some more power than he's shown, but right now, he's just a line-drive hitter," Quade said.

Quade doesn't know if he'll be able to get LeMahieu a start soon, with Darwin Barney, Starlin Castro and Aramis Ramirez already in the infield.

"As much as you'd like to get guys involved, I won't do anything at the expense of three guys that are playing well and that are healthy," Quade said.

LeMahieu said he added 15-20 pounds in the offseason at what some Cubs call "Camp Colvin." In the offseason, several players get together in Mesa, Ariz., to work on strength, nutrition and baseball. Tyler Colvin did it prior to the 2010 season.

Quade, Cubs pleased to see nice weather

CHICAGO -- Cubs manager Mike Quade exhaled a pleased sigh as he walked up the steps into the Cubs' dugout Monday to see clear blue skies and sunshine.

The game-time temperature for the first four games of the Cubs' current nine-game homestand was in the 40s, and the average temperature for the Cubs' first 28 home games was 52 degrees. But it was in the 80s as the Cubs took batting practice Monday.

"I don't need to see spring or fall for a few months," Quade said. "I really don't."

Quade is hoping the heat will ignite the Cubs' offense.

"I believe that all year long as the weather warms up our offense will be even better," he said.

Aramis Ramirez is one Cubs hitter who usually heats up with the weather. Ramirez has a career .302 batting average in June, compared to .261 in April/March and .269 in May. And Ramirez's career home run total of 66 in July, for example, is 26 higher than his total in April/March and 28 higher than his total in May.

Extra bases

• Geovany Soto didn't get a hit in his two rehab starts with Double-A Tennessee, but he was able to test his legs and had no problems. Soto played for the Minor League team before being activated from the disabled list on Sunday. He had been sidelined with a strained left groin.

"I ran for a little bit, and whenever I hit the ball, it felt good," Soto said. "In my head, I was a little concerned. I didn't want to [re-injure] it or feel it at all, and I never did."

• Brett Jackson, the Cubs' No. 1 Draft pick in 2009, was activated from Tennessee's disabled list. He had been sidelined since May 12 with a finger injury. Smokies pitcher Robert Whitenack was placed on the disabled list with a right elbow strain. Whitenack was 4-0 with a 2.39 ERA in seven starts.

• DJ LeMahieu, whose contract was purchased Monday from Tennessee, has played second and third but may get some action at first base in batting practice. Jeff Baker, placed on the 15-day disabled list with a strained left groin, was the backup for Carlos Pena at first base. Blake DeWitt is the Cubs' other option.

• Right-handed pitcher Jeff Stevens was designated for assignment to make room on the Cubs' 40-man roster for LeMahieu.