Updated

St. Petersburg, FL (SportsNetwork.com) - The Texas Rangers activated pitcher Yu Darvish off the 15-day disabled list on Sunday.

Darvish went on the DL last weekend, retroactive to March 21, with neck stiffness. He missed a scheduled spring training start late in March because of the issue and took a few days off, but threw a bullpen session this week without difficulty.

The 27-year-old right-hander was originally slated to start the season opener against Philadelphia on Monday.

Darvish was 13-9 with a 2.83 ERA in 32 starts last season after a rookie campaign of 2012 that featured a mark of 16-9 with a 3.90 ERA in 29 outings.

The Rangers optioned pitcher Nick Martinez to Double-A Frisco to open a roster spot. Martinez was in the line for the victory on Saturday in his big league debut against Tampa Bay after allowing three runs in six innings, but the Rays rallied for a 5-4 win.