Both Eckstein and McDonald landed on the 15-day disabled list on Thursday, retroactive to Wednesday, with Joe Inglett rejoining the roster and another move expected sometime before Friday's game at Cleveland.
Eckstein is still bothered by a strained right hip flexor, an injury he picked up while diving for a bloop into shallow left field in Tuesday's 5-4 loss to the Rays.
One inning after coming into the game to replace Eckstein, McDonald went down clutching his right ankle after catching a cleat on the turf as he tried to backhand a grounder.
The Jays added infielder Jorge Velandia to the roster on Wednesday and made sure Inglett was ready in case Eckstein and McDonald went on the DL. Inglett drove to Toronto from Triple-A Syracuse on Wednesday and camped out at a hotel, waiting for his phone to ring. The call came on Thursday, and Inglett found himself a member of the Blue Jays for the second time this season.
With one spot on the roster still free, the Jays are hoping to add another bat in time for a four-game series at Cleveland this weekend, in which they will face a trio of southpaws in C.C. Sabathia, Aaron Laffey and Cliff Lee.
"We've got three lefties going," manager John Gibbons said. "We want a right-handed bat that can hit lefties and give [Matt] Stairs a blow at the DH spot."
Pressed on who or what might be coming down the pipe, general manager J.P. Ricciardi was vague.
"We're looking for someone who can serve us in a role that helps us to have flexibility and do some things," Ricciardi said.
"It's all pending on a couple of things that I can't say right now. We've got some irons in the fire. Hopefully, we'll be able to see it through. If not, we'll have to go to Plan B."
Catcher Robinzon Diaz would have been a good fit, but he suffered a high ankle sprain in a home plate collision and is expected to miss three weeks.
Ricciardi said he's not interested in making a trade, meaning that if the Jays don't dip into their own system for a bat, the new face is likely to be someone who has recently been placed on waivers.
"By tomorrow we'll have something, either internally or externally," said Ricciardi.
Fears that McDonald, who was carted off the field after his injury, could miss a substantial amount of time have subsided. The defensive whiz is walking without crutches, but still has some swelling in his sprained ankle.
"I'm walking on it, but I can't run on it," McDonald said. "I wrenched it pretty good. The ligaments have got to heal up."
McDonald was reluctant to go on the DL, but recognized that waiting for him to heal was a luxury the Jays could not afford with Eckstein also hurting.
"I need to be able to move around laterally," said McDonald. "That's something that I can't do at a slow pace, so I'm not going to be able to do it at a fast pace. They need the roster spot, they don't want to play a man down for another day."
Eckstein was just as opposed to a forced vacation, Ricciardi said.
"He's a tough guy, he wants to play, but we have to look at the big picture," Ricciardi said. "He's not a 50 percent guy, he plays at 100 miles an hour. You've got to do him a favor and sit on him a little bit and let him slow down."
The physical demands of playing shortstop factored into the decision to give both players two weeks off.
"They're playing a position where they're moving so much," Ricciardi said. "Maybe in eight days they could be fine, but we're better off, at this point, just taking the time and letting them get through it. Two weeks is probably better than having them keep recurring and keep having that problem."
For now, Marco Scutaro will hold down shortstop with Jorge Velandia backing him up. Scutaro had a season-high three hits and two RBIs in Wednesday's 6-2 win.
"He got three hits last night, so we've got to ride him and run him out there. He's like Big Brown right now," joked Ricciardi, referring to Saturday's Kentucky Derby winner.
John Arthur is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.