(MESA, Ariz.) -- Pitcher Matt Garza is experiencing pain in his left side and will start the 2013 season on the disabled list, the Chicago Cubs announced Sunday.

Garza originally was injured on Feb. 17 during a batting practice session, causing him to miss 10 days of work. He returned to throwing this past week but during his second throwing session he reaggravated the injury.

"Now we know it is just time," Garza said. "We pushed it and pushed it hard. Everything felt great. Now it is the body saying, 'Let's take a little more time."

Garza made 18 starts last season compiling a going 5-7 with a 3.91 ERA and a 1.18 WHIP. His season came to an end in July due to stress reaction in his elbow.

With Garza out, Jeff Samardzija becomes the North Siders' opening day starter.

Samardzija went 9-13 with a 3.81 ERA and 180 strike outs last season.

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