Bob Bryan to reunite with brother Mike on tour in January

WATCH—Jim Courier announces Bob Bryan's return:

Bob and Mike Bryan are officially reuniting in January with Jim Courier breaking the happy news on Tennis Channel.

"He has good news that he's pain free right now," Courier said. "And he is planning to make his return in January back to the tour—which was not necessarily a given after his surgery."

Their exact start date has not been decided. It's really only bad news for Jack Sock, who's currently competing in the ATP Finals with Mike after winning Wimbledon and the US Open together. From the very start of their partnership during the grass season though, Sock has said he was just filling in.

Mike Bryan, currently ranked No. 1, qualified for the ATP Finals with both Sock and his brother.

"I want to finish the whole year," Mike Bryan said after winning Wimbledon. "To play with Bob or Jack, I mean, I'll be happy to be in London. If Bob can't come back, Jack's ready."

"I'm on standby," Sock said. "I'll be in the batter's box."

Mike and Bob Bryan have won a staggering 16 Grand Slam titles and 38 ATP Masters 1000s together. This season they won titles together in Miami and Monte Carlo.

Bob Bryan sustained a hip injury at Madrid that required a hip surface replacement with an artificial joint in August. The retirement was their first as a team in 1,407 matches. When Bob Bryan missed the French Open a few weeks later, it ended the brothers' Grand Slam streak together—which stretched back to the 1999 French Open.

WATCH—Mike Bryan speaks to Tennis Channel in London:

The twins turned 40 in April, just before Bob Bryan's injury. His expected recovery time was eight months, but he was hoping to cut it down to six.

"I've been watching him hit on camera. He's actually moving around the court pretty well. His rehab is going great," Mike Bryan said in London. "He's excited to come back. So 2019, Bryans are back."

Sock and Mike Bryan won their opening round in London on Monday over Marcelo Melo and Lukasz Kubot. Both wrote short messages to Bob Bryan on the TV cameras before walking off court.

This Week on Tennis Channel:

ATP Finals (Sun - Sun 11.11 - 11.18) - Novak Djokovic, Roger Federer and the world's best collide in the season Finale. Live coverage begins on Tennis Channel Sunday at 7:00am EST.