The Hungarian signed a new one-year deal with the Baggies this summer, but has been absent so far this season due to the knee ligament injury that he sustained last January.
Gera posted on his Facebook account: "It's a super feeling [to be back in training]. I have been looking forward to this day for a long time.
"I had surgery exactly seven months ago. I hope I'll be ready to play in three to four weeks, but I won't hurry."
The 34-year-old is in his second spell at The Hawthorns, having originally left them to sign for Fulham in 2008 before rejoining three years later.