Updated

New York Mets pitcher Johan Santana might not be ready for the start of the season after having his spring throwing schedule pushed back.

Santana has been tabbed to pitch the season-opener on April 1 and had his first throwing session this past Sunday. However, Mets general manager Sandy Alderson told reporters Friday that Santana needs to build arm strength and the possibility exists that the veteran might not be ready to pitch against San Diego to start the 2013 campaign.

The 33-year-old left-hander made just 21 starts in 2012 and was 6-9 with a 4.85 ERA. He didn't pitch after Aug. 17 because of a back issue.

Santana became the first Met to throw a no-hitter last June 1 against St. Louis. He was also out of action from July 20-Aug. 11 because of a right ankle injury.