He joined the A's at Tropicana Field on Tuesday for the start of a three-game set with the Rays.
"What I communicated to him [is that] what his role will be for us right now is length," said manager Bob Melvin. "We'll try to keep him stretched out to where he's potential added starting depth, which we're a little thin on. [General manager] Billy [Beane] is always looking to be incrementally better, and this is where we fell a little bit short, with length and another starter, so he fits in well.
"It's nice to have a guy who's pitched in different roles before and knows how to do it."
Francis started just one game for Cincinnati this season before being designated for assignment. In Triple-A Louisville, he was 4-3 with a 3.33 ERA in eight starts and said, "I feel like I've been sharp."
The 33-year-old southpaw split his time between Colorado's bullpen and rotation in 2013, marking the first time in his career he'd pitched as a reliever for an extended period. He struggled in both roles, pitching to a 6.27 ERA and 1.61 WHIP in 70 1/3 innings.
Melvin recalls a different version of Francis from his managerial days in Arizona, when Francis enjoyed much success in the Rockies' rotation, even finishing ninth in Cy Young voting in 2007. He also spoke to Reds manager and good friend Bryan Price, who relayed, "He's a great team guy and will do whatever you ask him to do."
"I'm ready to do whatever it is they need," confirmed Francis. "I don't throw quite as hard as maybe I did as a 23-year-old, but I still do mostly the same things. As a left-hander, just try to keep hitters guessing, not be too predictable."