The bruise is deep enough, according to head athletic trainer Kevin Rand, "It's probably going to be a good two to three weeks."
However long it lasts, it's going to be the third DL stint in what is becoming almost a lost season for Guillen. His latest injury happened on a play that saved a win for the Tigers.
"It's tough," Guillen said. "You try to keep yourself on the field, and it's getting tough for me this year."
Guillen's injury happened on the game-ending double play that salvaged the Tigers' 3-1 win over the Yankees on Monday night. A hard slide from Brett Gardner sent him directly into Guillen's knee as Guillen fired to first for the game's final out. Guillen limped off the field as Detroit celebrated.
An MRI exam taken Tuesday revealed no structural or ligament damage. An examination from New York Giants team physician Dr. Russ Warren at New York's Hospital for Special Surgery revealed his concern about the bruise.
Guillen said his knee has been more sore with each day, and it could worsen in the coming days before it begins to get better. The soreness, according to Rand, is expected to last for around two weeks or more.
"It was sore [Tuesday]," Guillen said Wednesday afternoon. "[Tuesday] night, it was more sore. And today, it's hard to walk."
With the Tigers already short a position player to make room for an extra reliever, they couldn't afford to go more than a few days shorthanded on the bench. Once they received the prognosis Wednesday night, they made the move they had readied Tuesday in case the MRI exam was bad.
"Originally, we thought day-to-day," Tigers manager Jim Leyland said. "But according to doctors, it's a really bad one. It's a shame."
To replace Guillen, Detroit recalled second baseman Will Rhymes from Triple-A Toledo. Rhymes filled in for Guillen at second when he went on the disabled list last month with a strained calf. Rhymes was originally in Wednesday's starting lineup, but a delayed flight out of Detroit prompted Leyland to replace him with Ramon Santiago.
Guillen played in seven games since coming back from the calf injury. He batted .214 (6-for-28) in that time with a double, a home run and four RBIs while providing a veteran bat behind American League MVP candidate Miguel Cabrera. Without him, the Tigers are again shorthanded by two quality bats, including Magglio Ordonez.
"It's a sad thing, really," Leyland said, "because the guy's worked his tail off to get back. You just wish for his and for your sake that he could stay healthy for a full season."
The 27-year-old Rhymes filled in admirably for Guillen and made an impression in his first Major League stint, batting .259 (14-for-54) with three doubles, a triple and four RBIs.
Jason Beck is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.