Ricciardo ended FP2 fifth fastest, and was just 0.390s off Lewis Hamilton's record lap time around the Austrian circuit.
The three-time F1 world champion set new fastest-ever laps of the Red Bull Ring in both Friday sessions, ending the day a tenth and a half up on title rival Sebastian Vettel's Ferrari.
Verstappen was the first to set a time as he enjoyed a bright start to the morning, and he quickly set about improving on it. Despite the excursion through the gravel, the only damage was to the side of the tire and Red Bull did not miss out on any running.
Thanks to escaping without serious sanction in Baku, where Hamilton was deprived of a near-certain race victory because his head-rest worked loose, Vettel holds a 14-point lead over the Briton, whose silence this week has spoken volumes.
The ninth race on the calendar is unlikely to create as many headlines as its predecessor, unless Vettel decides he quite fancies a one-race holiday.
Bottas finished ninth in this race previous year and fifth in 2014.
Fernando Alonso was eighth best in P2 on an encouraging day for the struggling McLaren team. After his maiden podium in Baku, Lance Stroll could only manage 15th and spun early on in the session at Turn 5. Immediately after his spin, Kvyat was passed by a limping Romain Grosjean as the Haas driver suffered a left front puncture after taking too much exit curb through the final two corners.
Elsewhere in FP1, Sirotkin was in at Renault and Celis in at Force India. In the battle of the Saubers, Pascal Wehrlein finished 1.5s ahead of Marcus Ericsson, who only completed 12 laps after his auto spent much of the session being worked on in the garage.