Haas will run a parallel brake programme during Barcelona's winter tests to determine which manufacturer it will use on its cars in 2017.
Haas endured a problematic finish to its debut F1 season last year, with numerous issues with its Brembo brakes in the final races. That prompted a test of Carbon Industrie brakes in Brazil to determine whether the issues were being caused by Brembo or complications with Haas' Dallara-built chassis, tests which continued at the finale in Abu Dhabi.
Steiner admits the team is still uncertain which way to go with the brakes and that both manufacturers are being seriously considered.
"On the brake supplier we will do a parallel programme and then find out which way to go," Steiner told ESPN. "We are going to make a decision after Barcelona test. We are ready to use either-or for the race season, so we are prepared to have options -- that was always our goal.
"We didn't say we ditched somebody, we just wanted to see what else was out there and have options if one showed to be a lot better. It could be either-or, we don't know yet."
The regulation changes for the coming campaign have presented a complication for Haas' decision, as the tests conducted last year were on cars much different to the models set to be on the grid this year. Steiner says the team's tests at the tail-end of 2016 simply led to the conclusion that both manufacturers were worth consideration for the coming season.
"You are absolutely correct. We couldn't test our brakes like they needed to be for this season, last year, so we planned for having the option. Last year we came to the conclusion the other material was good as well so we just need to double check everything for this year.
"The brakes are bigger now, the discs are wider, thicker. We just need to check the material and make sure it all works. The best way is always to have an option, if you can, and that's what we did."
Pre-season kicks off with four days of winter testing from February 27-March 2, before another four days the following week starting March 7.