Allen injured his Posterior Cruciate Ligament trying to recover an onside kick with 1:18 remaining in the 49-27 loss at Utah last Saturday, landing awkwardly on the sideline. But the extent of the injury was not immediately clear, head coach Jeff Tedford said Thursday.
"In the locker room after the game, he was fine. I had no idea about it until Sunday and Monday," Tedford said. "If you see him walking, he looks fine, but walking and running routes are two different things."
Asked if he had any regrets about going the onside kick down by 22, Tedford said "no, no. (We were) trying to get the ball back, trying to compete and score."
But Cal had declined to try an onside kick earlier in the fourth quarter, trailing by 29 points with 12:17 remaining after Allen caught a 23-yard touchdown pass.
"We didn't want to give them field position if we didn't get it," Tedford said. "They didn't bring their onside kick defense team on at that time (on the play where Allen was injured), but they did (earlier). With a minute and something to go, if they get it, then so be it."
Allen met with doctors and underwent an MRI on Tuesday, but will not require surgery to repair the PCL. There is a Chance Allen could play next Saturday in Cal's last home game against No. 2 Oregon or in the regular season finale on Nov. 17 at No. 13 Oregon State, Tedford said.
"We have to see how he recovers," Tedford said. "We're not going to put him in jeopardy by any means, definitely going to look out for his best interests."
Tedford conceded that Allen, regarded as a likely first-round pick should he declare for the 2013 NFL draft, may have played his final game at Cal, which sits at 3-6, 2-4 in Pac-12 play, and must win its final three games to become bowl eligible.
"I guess anything is a possibility, but all the NFL stuff we'll talk about after the season and take it one week at a time with him," Tedford said.
In just 33 games, Allen set a new school-record for career receptions with 205. Allen ranks third in career receiving yards (2,570) and his 17 career touchdown receptions are seventh most in school history.
Allen leads the team in receptions (61), receiving yards (737), and touchdowns (six) this season, and his average of 14.13 yards per punt return ranks third in the Pac-12 and 14th nationally.
However, Treggs is also dealing with an injury after spraining his ankle at Utah, leaving Rice-Eccles Stadium in a walking boot. Treggs, who has caught 21 passes for 216 yards and one touchdown this season, was able to practice Thursday, and Tedford said he would likely replace Allen on punt returns.
Powe caught two passes for 44 yards at Ohio State. The 6-foot-3, 212-pounder from Lakewood (Calif.) has played in eight games this season and made his first career start at Washington State.
Michalczik is pleased with the progress Powe has made and is looking forward to seeing what he can do with the opportunity.
"Darius has been great," Michalczik said. "He's a sharp young man and he works really hard, very focused. Can't say enough good things about him. Anytime you lose somebody, somebody has got to step up, and I think there are a couple guys that can fill that role.
"We've had a lot of true freshman that have played for us, and they had to play. It's like anything, it has been a growing process. They have been maturing, and it's not the end of the world. Those guys will step up and we're confident they will come out and have one heck of a game."
While Allen has been the focal point of the Cal passing game for the better part of the last two seasons, Michalczik doesn't necessarily see his absence as a death knell for the offense.
"The drastic change is you don't have ‘how do you get the ball to 21?' That's not the issue," Michalczik said. "Now the issue is how do we get other guys in position to make plays."
"Each week the plan changes and you do different things here and there, but people will fill in for him," Tedford said. "Those young guys are good players, and they are excited about playing, and I'm excited about seeing them play."
Dan Greenspan is the publisher of Cal Sports Digest and writes about the Pac-12 for Fox Sports Next. Follow him on Twitter @DanGreenspan