Caldwell, 26, has been a backup, possession-type and would be a back-of-the-rotation player for Denver. He had 37 catches for the Bengals last season; in 2009, he had 51 catches for 432 yards.
In other AFC West news:
The Raiders are reportedly are among the teams interested in Giants defensive lineman Dave Tollefson. The Bay Area native was on the Raiders practice squad in 2007. There is no movement on the Manny Lawson front. The Raiders are among several teams interested in him.