Reliever Steven Wright was also in the mix, but the knuckleballer was removed from contention when he pitched 5 2/3 scoreless innings on Thursday to pick up the win in relief of the struggling Ryan Dempster.
No matter who starts, there will be little, if any, Major League experience on the mound against Oakland's potent lineup. Workman has made one relief appearance for the Red Sox, having been groomed as a starter in Boston's farm system.
Workman made his Major League debut Wednesday, allowing three runs on four hits in two innings. After giving up a home run to the first batter he faced, the right-hander settled in to strike out four.
Britton is currently scheduled to start Sunday for Triple-A Pawtucket. The 24-year old has made one Triple-A start since being promoted from Double-A Portland, lasting 5 1/3 innings while allowing five runs on 10 hits.
The hole in Boston's rotation was formed when No. 4 prospect Allen Webster was sent down Wednesday after surrendering seven runs in just 2 1/3 innings against Seattle on Tuesday. Farrell said that he wanted Webster to improve his fastball consistency in Triple-A.
Jacob Thorpe is an associate reporter for MLB.com.