CHICAGO -- White Sox center fielder Luis Robert will not be able to resume baseball activities for 12 to 16 weeks after suffering a Grade 3 strain of his right hip flexor, representing a complete tear, during the first inning of Sunday’s 5-0 loss to the Indians at Guaranteed Rate Field.

That diagnosis came after the Gold Glove outfielder was examined by Nik Verma, the White Sox lead physician, at Rush Medical Center in Chicago Monday. Further consultation with specialists in the field will be needed to determine the next step for Robert.

Those options include surgical repair if in fact the tear affected the tendon’s attachment to the bone, or a rehabilitation process in which natural healing would take place without surgical intervention if the tear is contained to the muscle as opposed to the attachment between the tendon and the bone, according to general manager Rick Hahn, who shared the information with the media Monday night.

The White Sox placed Robert on the 10-day injured list and recalled infielder Danny Mendick from Triple-A Charlotte on Tuesday.

“Either way, coincidentally, the timeline is the same,” Hahn said. “We won’t know a timeline until after whatever the next steps are determined.

“But it’s safe to say in terms of projecting his possible return, it’s too soon to know. Quite frankly, we are not going to be able to provide you with an educated projection of that for another 12 weeks or so as we see how he progresses.”

Robert sustained the tear while beating out an infield single and appeared to be injured even before he hit the base and fell to the ground. It’s another major loss for a team with World Series championship aspirations and expectations, after left fielder Eloy Jiménez was sidelined for five to six months following surgery to repair a left pectoral tendon he ruptured while chasing a home run during Spring Training.

Depth beyond the frontline stalwarts is needed for every great team. But it’s tough to ask even an elite squad to overcome the departure of a five-tool talent such as Robert and a Silver Slugger winner with 40-home run potential such as Jiménez. But the goal remains the same for the White Sox, even if the challenge became significantly more difficult.

“It's obviously very difficult and not at all how any team draws things up. You certainly try to create as many contingencies and protections as you can,” Hahn said. “There are certain star-caliber players that are more difficult to replace than others.

“Obviously, now we're presented with another challenge, and with that challenge there's going to be opportunity for other players within the organization that's going to be something for [manager] Tony [La Russa] and the coaching staff to perhaps get creative with. It's going to be something for those of us in the front office to respond to potentially as well in the coming days and weeks. If we respond to this similarly to how the team has responded to Eloy, we'll be able to weather this storm.”

Jiménez’s injury moved Andrew Vaughn -- the team’s No. 1 prospect, per MLB Pipeline -- from first base/designated hitter to left field, despite his relative inexperience at the position -- just three Cactus League games. Vaughn has shown to be more than capable defensively, although he won’t have the comfort factor of playing alongside Robert for a while.

Yermín Mercedes, who was named American League Rookie of the Month for April, has been a DH revelation with a slash line of .395/.435/.628 over 23 games and 92 plate appearances. Leury García and Billy Hamilton will get the first looks in center, and Luis González will be the first young player added in Robert’s absence with a chance to take advantage of a big opportunity, as Mercedes and Vaughn have.

Hahn also indicated the team will look outside the organization for a possible replacement in center field. But once again, the White Sox have to balance giving up something for winning this year against a championship window they believe will be open for five to six years, and they understand moves are not prevalent during the month of May.

“We certainly went into this season with the intent to be aggressive and we haven't moved off that, in terms of our focus and expectations,” Hahn said. “That said, we are in the midst -- or the opening, I would say -- of what we hope will be the opening of an extended window.

“You certainly don't want to do anything shortsighted to short-circuit that, long-term. It's going to be a balancing act, and again, first you have to figure out what the options are before you figure out if the juice is worth the squeeze, so to speak.”

Two more injury updates were provided by Hahn.

Adam Engel, OF
Engel was sidelined at the end of Spring Training by a Grade 2 right hamstring strain, but a setback during the rehabilitation process put him back to square one for a return.

“At this point he is trending in the right direction and continuing to progress,” Hahn said. “However, we are currently approximately three weeks away from Adam to begin a rehabilitation assignment.

“That’s an approximate timeline. Our next update on him most likely will be when we are ready to announce he’s ready to begin a rehab assignment.”

Reynaldo López, RHP
The right-handed hurler’s season with Triple-A Charlotte will be slightly delayed due to surgeries on both eyes.

“He had surgery yesterday on both of his corneas to correct a vision issue he was having that was presenting him with blurred vision,” Hahn said. “He’s expected to make a full recovery and return to the active roster at some point in the next two to three weeks.”