Clearwater, FL (SportsNetwork.com) - Philadelphia Phillies pitcher Cole Hamels will not throw for a week after experiencing continued soreness in his left shoulder, the team's official site reported Thursday.

Hamels, who had already been ruled out for the start of the regular season due to inflammation in his throwing shoulder, told reporters his arm felt "fatigued out" after a bullpen session this past Saturday.

"I believe I threw 35 pitches. To my body, it felt like a thousand," Hamels said. "It just wasn't healing up or getting that response back so I could go out and do it again. I didn't feel like it was safe to push it in that direction because I think that would have led to injuries."

The Phillies do not plan to have Hamels undergo an MRI or receive a cortisone injection, though the setback could conceivably keep the three-time All-Star sidelined until May.

Hamels is coming off a somewhat disappointing 2013 campaign in which the 29- year-old went just 8-14 with a 3.60 earned average in 33 starts.