Treinen (arm) didn't feel right after playing catch Saturday and could return to the injured list, David Vassegh of AM 570 LA Sports reports.
Shoulder troubles sidelined Treinen from mid-April through early September. While he's thrown a pair of scoreless innings since his return to action, his arm issues have resurfaced. Whether or not a potential trip to the injured list would be brief or season-ending remains to be seen.