Paredes, 25, batted .192/.231/.248 with one home run and 48 games with the Astros last season. He's a career .234/.274/.311 hitter in three major league seasons.
The Marlins selected Paredes off waivers in November.
Paredes is a switch-hitter, but he's posted a career .264 average against right-handers and a .143 average against left-handers. All three of his home runs have come from the left side.
"Jimmy Paredes is a versatile player. He can play a couple of positions in the infield and outfield," said executive vice president Dan Duquette.
"He's a switch-hitter, is only 25 years old and he's got some major league experience."
Paredes has played second base, third base, left field and right field in the majors. He's also played shortstop and center field in the minors.
The Orioles will need to clear a spot on their 40-man roster after Suk-min Yoon signs his three-year deal.
As for today's workout, pitcher Miguel Gonzalez stopped halfway through as a precaution because of back spasms.
"We'll see what tomorrow brings," said manager Buck Showalter.
Pitcher Alfredo Aceves and catcher Johnny Monell are expected in camp on Sunday. Monell's flight was cancelled today, causing another delay.
The backup catching candidates have been told by bench coach John Russell that the job will be won with defense.
Monell and Steve Clevenger figure to battle it out, though the Orioles may search outside the organization later in spring training as more catchers become available.