Coman and Hernandez came off the bench in the second half of last Sunday's goalless draw at home to Leipzig for their first appearances after long-term injuries.
Head coach Hansi Flick says the pair could start for the German league leaders at strugglers Cologne, who are six points above the relegation places.
Flick is eager to build up the French pair's fitness before facing Chelsea in the Champions League last 16, first leg at Stamford Bridge on February 25, with the return in Munich on March 18.
"We're glad that it was (relatively) quick for both of them," Flick said Friday, with winger Coman back after twisting his knee in the Champions League win over Tottenham last December.
Centre-back Hernandez, the most expensive player in Bayern's history after costing 80 million euros ($87 million) from Atletico Madrid last year, was out for four months with an ankle injury.
"Both are doing well in training, but we don't yet know whether they will last 90 minutes.
"What's clear is that they need more practice. Whether they come on or play from the beginning is open."
Flick said he hopes that by the time Bayern first face Chelsea, both "should be at 100 percent".
Bayern start the weekend a point clear of nearest rivals Leipzig, who host relegation-threatened Werder Bremen on Saturday.
Flick says Bayern captain Manuel Neuer, who missed training in midweek with a stomach virus, will face Cologne.
Winger Alphonso Davies and midfielder Joshua Kimmich also took part in training after carrying knocks.