Showalter said Davis' oblique strain is not the most severe type -- it appears to be a medium-grade strain or tear -- but the normal recovery time from the injury is more than the DL period.
The Orioles officially placed Davis on the disabled list before Sunday's game, retroactive to Saturday, and the club announced that a corresponding move will come at a later time.
The Orioles will play a man down in today's series finale against Kansas City. The club is off tomorrow, and Showalter said he will have 25 active players Tuesday when the Orioles open a two-game home series against the Pittsburgh Pirates.
The Orioles could add another pitcher Tuesday, and they're permitted to recall left-hander T.J. McFarland, who is scheduled to start at Triple-A Norfolk that day, before the mandatory 10-day option window because he would be replacing a player going to the DL.
McFarland could come up for bullpen depth Tuesday and then return to Triple-A the following day because the Orioles must activate left-hander Troy Patton from the restricted list Wednesday. Patton will have completed his 25-game suspension for testing positive for a banned amphetamine.
Showalter emphasized again that third baseman Manny Machado's minor league rehabilitation assignment won't change because the club is without Davis.
After playing his third game at High-A Frederick this afternoon, Machado will either stay for another game in Frederick, report to Triple-A Norfolk or take the day off and rejoin the Orioles on Tuesday.
Davis will either go with the team on their upcoming road trip to Minnesota and Tampa Bay, head to Sarasota, Fla., to rehab or remain in Baltimore to work with trainers here. Davis is lobbying to join the team on the road.
-- Before Sunday's game, the Orioles announced that they've released utility player Steve Pearce. He was designated for assignment Tuesday to make room for McFarland.
-- Right-hander Bud Norris is still on track to start Wednesday against Pittsburgh. He was set to throw a side session today to test his right hamstring, which he tweaked in his last start Thursday.
-- Kevin Gausman threw 4 2/3 innings for Triple-A Norfolk on Saturday night, but he left the game after 75 pitches. Showalter said the organization is keeping Gausman on a pitch count to ensure he can help the big league team late in the season and in any possible postseason situation.
--Delmon Young isn't in today's starting lineup and has played just once in the past eight days, but Showalter assured that Young will be in the starting lineup when the matchup is right. Young is just 3-for-14 against Kansas City right-hander James Shields, who is a former teammate of Young's in Tampa Bay.
Here are today's starting lineups:
Jemile Weeks DH
Nelson Cruz RF
Nick Markakis 1B
Adam Jones CF
Steve Clevenger C
J.J. Hardy SS
Steve Lombardozzi 2B
Jonathan Schoop 3B
David Lough LF
Miguel Gonzalez RHP
Nori Aoki RF
Omar Infante 2B
Eric Hosmer 1B
Billy Butler DH
Alex Gordon LF
Salvador Perez C
Mike Moustakas 3B
Alcides Escobar SS
Jarrod Dyson CF
James Shields RHP