Ace right-hander Roy Halladay was hampered by lower back and shoulder problems last year.

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Howard has also endured back and shoulder problems (it's uncertain if he will play against the Nets) as he prepares to become a free agent this summer.

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Johan Santana, for instance, missed all of 2011 recovering from shoulder surgery and a third of last year due to ankle and back problems, and so he's only pitched 324 innings over the last three years.

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