Lorenzo Alexander recorded 1.5 sacks and a fumble recovery against Minnesota. (Jonathan Newton/The Washington Post).

Washington Redskins defensive coordinator Jim Haslett has spent the last four weeks experimenting with his personnel, trying to find a replacement for pass-rusher Brian Orakpo.

 The coach went almost exclusively with the tag team of Rob Jackson and Chris Wilson for the last three games, but on Sunday added fellow linebackers Lorenzo Alexander and Keenan Robinson to the rotation.

 The latest implementation did the trick as Alexander — who for the last six years has played primarily on special teams while also seeing time at eight positions on both sides of the ball – had an active day as he helped the Redskins defense record a season-high four sacks in their win over the Vikings.

 Alexander recorded a team-high 1.5 sacks, five tackles, four quarterback pressures and a fumble recovery that put Washington in position for its second touchdown of the game.

 Alexander’s first big play came with 2:26 left in the second quarter, when Vikings quarterback Christian Ponder fumbled the ball at his own 13-yard line. Alexander plucked the ball out of the air and returned it to the 6-yard line. At first, the play appeared to be an interception but was changed to a fumble because the ball was knocked out of Ponder’s hand before it came forward with it in a throwing motion.

 Inside linebacker Perry Riley ran a stunt, blitzing from the left edge and driving running back Adrian Peterson back into Ponder. The ball was jarred free and went into the air and into Alexander’s hands.

 “Some of that’s being in the right place at the right time,” Alexander said with a grin. “It was more Perry doing a great job rushing. It was a blitz, both guys coming off the edge. Perry did a good job pushing the back into the quarterback. … I was in the right place. I was able to catch it, wish I could’ve scored, but had [Vikings tackle Matt] Kalil all over my back.”

Later in the same quarter, Alexander and defensive end Stephen Bowen combined for a sack. Then in the fourth quarter, with the Vikings facing second and one at the Washington 49-yard line, Alexander knifed through the line and dropped Ponder for a nine-yard loss.

 The 1.5 sacks were a single-game career high for Alexander.

 “Lorenzo is an outstanding athlete. He just waited for his opportunity,” Bowen said. “Everyone knew he could pass rush, and he took advantage of it. We were scheming it up for him all week, and we knew that they weren’t going to be ready for the stuff we were running with Lorenzo.”

Alexander’s big day marked his most extensive action on defense since he split time at outside linebacker with Andre Carter in 2010.

“It was great,” Alexander said of the day. “I understand what my role on the team is: to be a special teams demon and a captain and fill in on defense when needs be and take advantage of my opportunities. I know I can play in this league. Losing the weight [30 pounds in the last year] has made me a different player, quicker, more dynamic and i think the coach was able to utilize my history as far as playing [defensive] tackle in some of our game today. It was a great feeling to go out there and finally contribute on defense and win.”