Last week, the Mets delayed Santana's first spring start so he could build more arm strength. Sandy Alderson said Santana hasn't experienced any pain and there is no structural damage in his shoulder.
Assuming Santana doesn't suffer any further setbacks and he does start pitching in games on or around March 10, he will have four starts before Opening Day, with his last start coming around March 25. It's technically possible for him to accumulate enough innings in those five starts to get ready. But I still have major concerns about Santana's ability to be ready for the start of the season, whether it's Opening Day or sometime during the first part of April.
Santana was shutdown last August and later placed on the disabled with what the team characterized as lower back stiffness. Alderson said last month that Santana also suffered last summer from general fatigue due to his rehabilitation from shoulder surgery he underwent in September, 2010.