Ashby will fill in on play-by-play duties when Brown skips occasional road trips as part of his scaled-back schedule. MLB.com reported last month that former Astros player Geoff Blum had agreed to provide color analysis on television while Ashby was calling game action.
Astros games are moving this year to CSN Houston, a television partnership between the Astros, NBA's Houston Rockets and NBC Sports that was launched last year.
Robert Ford, who has done pregame and postgame work for the Royals, will be announced as the team's new radio play-by-play voice, a source told MLB.com. He takes over for the Hall of Famer Milo Hamilton, who retired from full-time duties following last season. A source also told MLB.com former knuckleball pitcher Steve Sparks, a Houston resident who has done studio analysis work on Astros broadcasts the last few years, will be the color analyst for radio.
Ashby worked alongside Hamilton from 1998-2006 before taking a job with the Toronto Blue Jays. He still lives in Houston.
"The opportunity in Toronto was, for me and my wife, a life-saving and career-saving kind of opportunity, and all I can do is thank them for that and everything it's been to us," Ashby said last month. "It's really given me this opportunity now to come back here and pursue this chance, and I'm just grateful to come back home and work and just kind of continue to enjoy what this special vocation presents."
The retirement of Hamilton, the loss of television analyst Jim Deshaies to call Cubs games on WGN and the dismissal of veteran radio announcers Brett Dolan and Dave Raymond following last season required the Astros to hire nearly an entire new broadcast team.
Houston opens Grapefruit League play Feb. 23 against the Phillies in Clearwater, Fla.
Brian McTaggart is a reporter for MLB.com and writes an MLBlog, Tag's Lines. Follow @brianmctaggart on Twitter. This story was not subject to the approval of Major League Baseball or its clubs.