Manager Mike Redmond said Tuesday he decided to keep Solano over Reid Brignac because of Solano's ability to play second, third and shortstop, as well as steal some bases.
Solano hit .252 in 310 at-bats for the Marlins last season.
Kelly signed with Miami as a free agent during the offseason. The seven-year veteran spent the past six seasons with Detroit and gives Miami some added offense off the bench.
"I'm happy with the ball club that we have position player-wise right now," Redmond said. "Now we just go out and have fun the next couple days and get ready to get this thing going."
Brignac, in camp with a minor league contract, could elect to become a free agent. Outfielder Jordany Valdespin has been told he will begin the season in the minors.