The spring practices in many ways are more for the young players than for anybody else. Any established veteran who has been with the team for a while, whether they are a starter or not, is already going to know just about everything in this instructional phase unless there has been some coaching change as well.
Now that doesn’t mean that OTAs are just going to be a glorified rookie minicamp or anything like that, of course. The veterans are going to get their time on the field, as well, but they are also going to get their days off, both for maintenance and for the opportunities to get other people in the rotation.