Paging Dr. Bob. Bob Newhart has been booked into Chicago General for a three-episode stint on ER.

The master of comedy timing tackles a rare dramatic role as an architect suffering from macular degeneration, an eye disease that plagues real life celebrities Mary Walsh (This Hour Has 22 Minutes) and Dabney Coleman.

Newhart's star turn will occur in October and November. Joining ER full-time this fall is Linda Cardellini (Scooby-Doo, Freaks And Geeks) who will appear in late October as a nurse and single mother.

Cardellini joins Parminder Nagra, the young Bend It Like Beckham star who will play a third-year British med student.

The series returns for a 10th season Sept. 25 on CTV and NBC.

They'll help take up the slack for Noah Wyle, the ER original who will be taking a three-month break after the first two episodes this season.

In other NBC casting news, Gary Cole has added to the cast of The West Wing as President Bartlet's new vice-president.

Cole, who will show up around the third episode, plays Robert "Bingo Bob" Russell, a congressman from Colorado.