Mercedes were given a huge shock when Nico Rosberg decided to announce his retirement from Formula One just days after winning his maiden world championship.
The Silver Arrows were forced to delve into the market to find a replacement and they eventually brought in Bottas from Williams after a lengthy search that had linked several names to the vacant position.
Both Hamilton and his new team-mate appear to be getting on well after two positive testing stages in Barcelona and everything looks good for the defending constructors' champions going into the season-opener in Australia this weekend.
However, Bottas has only been given a one-year contract at the Brackley-based outfit and Lauda admits the team will analyse how the two drivers work together.
He told the Austrian broadcaster ORF: "We're going to start with Bottas and Hamilton and see how it goes."
Lauda also rejected claims suggesting Mercedes are lining up a swoop for four-time world champion Sebastian Vettel, who is set for his third year at Ferrari.
He added: "That is not our plan - I must say that quite clearly."