They have 2 new guys to work in. It takes more than a quarter or 2 in pre-season to build line cohesion. It might be midway through the season before they gel together. It's a process.

Same thing goes for WR - Robinson. Remember how few targets OBJ had his first few games vs how he and Stafford worked toward the end of the year. You don't just plug a new guy in and go.