Anderson said he got hurt Tuesday. He only had a few throws left when he abruptly felt pain "like somebody stabbed me in my side,'' he said.
Anderson, a former 14th-round pick who made his major league debut in 2018, missed a chunk of last season with an injured trapezius muscle in his neck and back. He had spent the offseason strengthening his core and diligently working back from that injury, only to find out he essentially will miss spring training this year.
Anderson went 3-0 with a 5.55 ERA last season in 54 appearances with the Angels. He is fighting for a spot in Los Angeles' bullpen again this year.
The Associated Press contributed to this report.