Murray on Friday took the late decision to play in Spain after a surprise defeat at the hands of Spaniard Albert Ramos-Vinolas in the last 16 of the Monte Carlo Masters.
Murray had been scheduled to play just Madrid and Rome ahead of the French Open. The Scot had suffered an elbow injury in March, and only made his return from a five-week layoff on Wednesday in Monaco.
It has been a tough start to 2017 for Murray after finishing last year as the world’s top-ranked player. His run of 28 consecutive wins was brought to an end by Novak Djokovic in Doha in January, while unheralded Mischa Zverev ended Murray's hopes of a maiden Australian Open title in Melbourne.
Murray won his first tournament of the year in Dubai last month, but a week later suffered a shock defeat to world number 129 Vasek Pospisil – his first loss to a player outside the top 100 in six years.