Chief Justice John Roberts has been on the Court for 13 years now, and he is generally perceived as a conservative.
But he has surprised some conservatives, as when he kept ObamaCare (the Affordable Care Act) alive in 2012.
Also, Roberts has often stated by the doctrine of “Stare Decisis”–to stand by things decided”–although he has not been consistent on this over the years.
The odds of Roberts siding with the liberals on the Court for the image of the Court named after him as Chief Justice, is a thin measure of what kind of balance he might present on the future Supreme Court.
It seems likely that on balance, he will be “number 5”, in the middle, but that middle will be much farther to the Right than Anthony Kennedy or Sandra Day O’Connor represented.
But then again, Justices have surprised their Republican Presidents who appointed them, as with Earl Warren and William Brennan under Dwight D. Eisenhower; Harry Blackmun under Richard Nixon; John Paul Stevens under Gerald Ford; O’Connor and Kennedy under Ronald Reagan; and David Souter under George H. W. Bush.
The best estimate is that no one should count on John Roberts avoiding “his” Court from being regarded as the most right wing, conservative Court since the time of Warren G. Harding. Calvin Coolidge, and Herbert Hoover nine decades ago, before the Great Depression and New Deal began the transformation of constitutional law.