TEMPE, Ariz. - A benign, baseball-size tumor has been removed from the chest of Arizona Cardinals defensive end Kenny Iwebema.

Coach Ken Whisenhunt says the surgery was performed on Monday. The tumor was discovered during routine X-rays on April 30, the day before the start of minicamp.

Iwebema showed no symptoms and that the condition could have been life-threatening had it gone undetected, Whisenhunt said after the team’s voluntary workout on Wednesday.

“Because it didn’t show up the year before, it appeared to be something that had grown very rapidly,” Whisenhunt said.

Iwebema, a fourth-round draft pick out of Iowa in 2008, can begin some rehabilitation work in two to three weeks but isn’t expected to resume football activity for six to eight weeks.

Doctors were able to use a minimally invasive laparoscopic procedure to remove the tumor through Iwebema’s side.

“It was very close,” Whisenhunt said. “Had it (the tumor) been a little bit bigger, they would have had to crack his chest, which would have put him out for the year.”

Trainer Tom Reed said there was no sign of the tumor in X-rays taken when Iwebema was at the rookie combine 14 months ago. Iwebema was feeling fine when he showed up for minicamp.

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“He had absolutely no symptoms,” Reed said, “no shortness of breath, no weakness to the upper extremities, nothing like that.”

Once a person experiences such symptoms, Reed said, the tumor has grown to put pressure on the lungs or heart. The growth was located between the sternum and the heart.

Iwebema participated in the last two days of minicamp, where all the work is non-contact. Further tests showed that the tumor was growing rapidly and had to be removed as soon as possible.

Had the tumor gone undetected, there was a danger of shock to the heart with a hard hit to the sternum, Reed said.

Meanwhile, quarterback Kurt Warner was cleared for full activity at this week’s voluntary workouts. After undergoing hip surgery, he had been limited during minicamp.

Wide receiver Anquan Boldin and defensive tackle Darnell Dockett — both in contract disputes with the Cardinals — are not participating in the three days of practice that end on Thursday.

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