Best missed last weekend's goalless draw against West Brom having ruptured a fat pad and tore ligaments around his knee, but he trained on Thursday and is available for selection against the Royals.
Westwood went into the clash against the Baggies nursing a back problem and was forced off after just 10 minutes, with Dimi Konstantopoulos coming off the bench to put in a sterling display.
The Republic of Ireland goalkeeper also trained on Thursday, although not fully, and manager Chris Coleman will assess his fitness over the next 24 hours before coming to a decision. But the Sky Blues boss insists Westwood will only be involved if he is 100%.
Aron Gunnarsson will definitely not start against Brendan Rodgers' struggling side but Coleman will also keep a close eye the midfielder as to whether he could play a role from the bench.
Captain Stephen Wright (flu) and Elliott Ward (back) should be okay, David Bell (ankle) is again likely to be on the bench having managed 83 minutes for the reserves, but the game will come too soon for James McPake despite the defender's return to training. Sammy Clingan (broken toe) remains out.
Reading captain Ivar Ingimarsson will return for the trip.
Ingimarsson missed the 1-0 defeat at home to Leicester on Monday night thanks to a one-match suspension but will come straight back into the side as manager Brendan Rodgers looks for a much-needed win.
Forward Noel Hunt had surgery on his knee injury this week and is expected to be out for some time, while left-back Chris Armstrong is still recovering from knee surgery of his own.
On-loan Celtic defender Darren O'Dea is hoping to be involved after missing the Leicester match with a groin problem as the Royals seek to end a run of four straight defeats which has left them in the relegation zone.