Chamberlain, in camp as a non-roster invitee, is the fifth pitcher to have a spot in the bullpen locked down after Cody Allen, Bryan Shaw, Jeff Manship and Zach McAllister. Tommy Hunter will be the sixth once he returns from core muscle surgery in mid-May. That leaves two spots up for grabs, one probably having to go to a left-hander.
The club also optioned third baseman Giovanny Urshela, relief pitcher Austin Adams, outfielder Joey Butler and infielder Erik Gonzalez to Triple-A Columbus. Urshela played well this spring, hitting .308 with a team-high five home runs this spring, but doesn't have a spot on the roster with Juan Uribe and Jose Ramirez covering third base.