COMMERCE CITY, Colo. – The Colorado Rapids will be without captain Pablo Mastroeni for a minimum of six weeks due to the re-occurrence of post-concussion symptoms, the midfielder told MLSsoccer.com on Sunday afternoon.

While watching the Rapids defeat the Fire 2-0 at Dick’s Sporting Goods Park, Mastroeni said team doctors advised him to sit out six weeks, and he would be re-assessed at that point in time.

Mastroeni said he’d been sleeping poorly and feeling various post-concussion symptoms since taking a blow to the head in the Rapids’ season opener March 10. Mastroeni’s concussion problems first began last October, when a collision with Real Salt Lake defender Jámison Olave forced him to miss the rest of the regular season and the MLS Cup Playoffs.

The veteran has also consulted former New England Revolution forward Taylor Twellman about his battles with post-concussion symptoms, and those conversations have helped convince the former US international to take a cautious approach to the injury.

“It’s the real deal,” Mastroeni said.

Mastroeni repeatedly expressed concern for his health once his career ends, saying he wanted to prioritize his wife and children and avoid a similar fate to other former players in MLS and the NFL who have suffered comparable issues. Mastroeni also offered praise for the Rapids training staff in its handling of his concussion problems.

“They’ve been awesome,” Mastroeni said.

Martín Rivero, who impressed in his MLS debut Sunday afternoon, is expected to take Mastroeni’s place in Colorado's starting lineup while Mastroeni is out. Wells Thompson and Ross LaBauex are other options in the midfield as well.

The club returns to action on Saturday at Real Salt Lake.