While teams have been actively negotiating with free agents since the first of the month, most contracts can't be signed during the July Moratorium, when the league does much of its yearly bookkeeping to determine figures like the salary cap and luxury tax lines. First-round rookie scale contracts are one of the exceptions to this rule, as the salaries in these contracts are not dependent on cap figures, and teams are allowed to sign first-round draft picks even if over the cap. Lottery picks generally sign ahead of summer league play, though sometimes signings are delayed in order to maximize cap space during free agency.
Parker's exact contract terms are not yet known, but we can assume he'll sign to the usual 120% maximum of his scale amount. For the 2nd pick in the 2014 draft, that works out to about $4.9 million for this coming season. The difference between that number and Parker's $4.1 million slot comes out of Milwaukee's cap room, but it's a negligible figure considering Milwaukee's modest salary commitments at the moment, not to mention the Bucks' general lack of urgency in free agency thus far. The Bucks' cap space currently sits at around $11.3 million including the non-guaranteed deal of Chris Wright. Parker's deal will also guarantee him a $5.2 million deal next year with team options for the following two seasons at $5.4 million and $6.8 million.
Milwaukee's two second round draft picks remain unsigned and carry no cap hold until they sign. Damien Inglis will not play with the Bucks in the Las Vegas Summer League due to injury, but Johnny O'Bryant is on the roster.
Update: Charles Gardner confirms that Parker's contract is for the 120% scale amount.