HOCKENHEIM, Germany -- Mercedes boss Toto Wolff will use Formula One's August break to decide whether Valtteri Bottas will continue on as Lewis Hamilton's teammate in 2020.

Bottas' Mercedes contract runs until the end of the current year. The Finn started the season strongly with victory at the Australian Grand Prix but has only been on the top step on one occasion since, in Baku, as Hamilton has taken a stranglehold on the championship battle.

Complicating matters for Wolff is that highly rated Mercedes junior Esteban Ocon is waiting in the wings, while speculation continues to mount about Max Verstappen's future. Mercedes used the buildup to its home race last year to confirm new deals for both its drivers, but Wolff is in no rush to do similar ahead of this weekend's German Grand Prix.

"We want [Bottas] to end the season before the shutdown in a good place and put in two solid performances in Hockenheim and Budapest, and then spend some time thinking about the driver lineup for 2020 and beyond," Wolff said.

"It is pretty unusual to announce drivers in July. If you want to take all the time, you properly need to assess and you can even drag it into the winter, like we have seen in some other teams, and it was a standard in the past.

"For us it is not only about making the right decision for next year but looking ahead, and this is why we agreed that we will take the decision in August going forward, but it doesn't necessarily mean we will announce it in August."

Valtteri Bottas' future is uncertain beyond the end of 2019. Dan Mullan/Getty Images

The presence of Ocon has created a headache for Wolff. Ocon was the biggest loser in last year's dramatic and unpredictable driver market, with a Renault deal seemingly falling apart at the 11th hour as the team secured the signature of Daniel Ricciardo. Ocon was also linked with McLaren, but the team was unwilling to pick up someone closely affiliated to Mercedes, while hopes of a move to either Racing Point or Williams came to nothing.

Ocon has remained with Mercedes this year as the team's reserve driver but has not raced elsewhere. Wolff is fully aware of the ramifications on failing to secure Ocon a seat for the 2020 season.

"As we all know it was an unfortunate situation last year that Esteban fell between the chairs," Wolff said. "He could have chosen between two seats and in the end nothing came out.

"From our perspective everyone knows about his driving capabilities for Mercedes. Valtteri is showing some very strong performances and merits the seat, but equally Esteban has shown that in the past and is a great addition to the team.

"He contributes a lot a lot behind closed doors, he drives the sim overnight on race weekends, he comes in here Saturday and gives us input and he is a great kid overall.

"Putting a Mercedes young driver in the car would be interesting as well. Having said that, there is interest for Esteban among other teams and we need to carefully make a decision for ourselves and with the other interested parties, not only for our own benefit but also for Esteban's benefit.

"If it would be that we were taking a decision in favour of Valtteri, it clearly also means that somebody else would continue to develop him [Ocon] and would mean we would lose our hand for a year or two or more on Esteban. These are the consequences of that decision."

McLaren is the only team to have made any sort of driver announcement this year, confirming Lando Norris will remain alongside Carlos Sainz in 2020.