4:03pm: Jeremy Lamb has also signed his rookie deal, according to Mark Berman of FOX 26 Houston (Twitter link). Assuming he signed for the full 120%, the 12th overall pick will earn $2,020,200 in his rookie season.
3:46pm: A pair of Rockets first-round picks, Royce White and Terrence Jones, have signed their rookie contracts, according to Jonathan Feigen of the Houston Chronicle (via Twitter). The team's other first-rounder, Jeremy Lamb, is expected to sign in the coming days.
With Houston exploring a variety of roster moves this offseason, including trying to trade for Dwight Howard, it made sense that the team's three first-round picks had yet to sign. Now that White's and Jones' deals are official, their first-year salaries will officially show up among Houston's 2012/13 commitments. As the 16th and 18th overall picks, White and Jones will likely be in line for salaries of $1,645,440 and $1,485,000, respectively.
The two rookies are also ineligible to be traded for 30 days now, though if the Rockets wanted to include them in a deal for Howard or another player, the team could reach an agreement and then finalize the deal after that 30-day period.