Just when the Gophers found a rhythm to their passing game, they’ve lost their top wide receiver because of a knee injury.

Derrick Engel injured his knee during a one-on-one passing drill in Sunday’s practice, leaving him doubtful for Saturday’s showdown against No. 16 Wisconsin.

There was Internet speculation that Engel had suffered a torn anterior cruciate ligament, which would end the redshirt senior’s college football career, but coach Jerry Kill said he first needed to see the results of Engel’s MRI exam.

“I’m not going to [speculate],” Kill said. “That’s the worst thing you can do. It could be a medial [collateral] ligament, it could be cartilage. Until you get an MRI, you don’t know those things.”

Still, either of those injuries likely would cost Engel the final two regular-season games, at least. That would be a big loss for the Gophers, especially against Wisconsin and Michigan State — two of the top five scoring defenses in the country.

Engel leads the Gophers with 25 receptions for 405 yards and five touchdowns. They don’t have another wide receiver with more than eight receptions or a single touchdown catch this season.

That list includes freshman Drew Wolitarsky (eight catches, 109 yards), junior Isaac Fruechte (8-97), freshman Donovahn Jones (6-79), sophomore KJ Maye (6-70) and junior Logan Hutton (3-31).

Redshirt freshman tight end Maxx Williams is second on the team with 17 catches for 299 yards and four touchdowns, followed by running back David Cobb (14-148).

Engel’s emergence was critical for a team that since last season had lost receivers A.J. Barker, Devin Crawford-Tufts and Andre McDonald.

“We’ve had people make some catches,” Kill said. “Derrick [Engel] and Maxx Williams, and a lot of people haven’t realized how good those two freshmen [Wolitarsky and Jones] are starting to play.”

The Gophers averaged only 117.7 passing yards through their first seven games, but that number jumped to 223.3 yards over their past three games.

Wisconsin has the nation’s seventh-best rushing defense (98.8 yards per game) but was vulnerable against the pass in losses at Arizona State and Ohio State. The Sun Devils passed for 352 yards, and Ohio State quarterback Braxton Miller threw for four touchdowns.

The Badgers have a talented front seven but have more holes in the secondary. Without the speedy Engel, the Gophers would have a harder time exploiting the defensive backs.

Gophers quarterback Philip Nelson said it was difficult seeing Engel get injured.

“You’re a little worried,” Nelson said. “You see a receiver go down, and we’re not particularly deep there, and Derrick’s a great player. So you wish the best for him, and hopefully he’ll be able to play [Saturday]. We’re not sure yet, but once again I’m confident in our [other] receivers.”

Engel could become the team’s third starter to go down with a season-ending injury. Junior cornerback Briean Boddy-Calhoun tore an ACL in the season’s second game, and redshirt sophomore center Jon Christenson broke a leg in the Nov. 2 victory at Indiana.

Etc.

• Kill said he will coach from the coaching booth Saturday for the fifth consecutive game, with Tracy Claeys continuing to serve as acting head coach on the sideline. “That’s the best situation for our football team with where we’re at right now, and what’s best for me,” he said. “We’re not going to change anything. It’s worked pretty well.”

• Saturday’s forecast calls for a high of 20 degrees. “That’s kind of what it’s all about,” Kill said. “You play old-fashioned football and you play outdoors.”