The Venezuelan driver joined from Williams at the end of the last year and will continue his Lotus career for at least another season.
"I don't want to give too much away, but as it's halfway through the season I can confirm 50% of our driver line-up for 2015 as Pastor is with us for next year," Lopez told the team's official website.
"Despite the difficulties we've had so far this season, he recognises our true potential as a team and we recognise his true potential as a driver. We will achieve great things together."
Maldonado is yet to pick up any points in the current campaign.