Warren, a three-time winner on the circuit but back facing this test after finishing 217th in the 2019 Race to Dubai, carded a four-under-par 67 in his third round on the Lakes Course at Lumine Golf Club in Tarragona.
The five-birdie effort lifted him into a share of 34th spot on four-under as he bids to finish in the top 25 and ties.
Five of the Scottish hopefuls are on course to make the projected cut after 72 holes, led by Kingsbarns Pro Academy player Daniel Young and rookie pro Euan Walker.
Young, who won the Eagle Orchid Scottish Masters in Aviemore on the PGA EuroPro Tour earlier this year, added a 72 to his back-to-back 69s to sit joint-26th on five-under.
Walker, who joined the paid ranks in September straight after the Walker Cup, is on the same total after a 70 that contained four birdies.
Craig Howie (70) sits in joint-46th on three-under, a shot ahead of Ewen Ferguson (69), with Liam Johnston the odd man out after a 76 left him sitting four shots outside the projected cut on two-over. Dane Benjamin Poke extended his lead to two shots after signing for a 69 on the Hills Course, with Dutchman Lars van Meijel moving into second spot following a 65.
Australian Brett Rumford sits outside the projected cut of two-under, as do former Dunhill Links champion Michael Hoey and Italian Matteo Manassero, the youngest winner of the BMW PGA Championship.