Not unlike how the Vikings brought oft-injured tackle Jake Long out of semiretirement last year, a critical injury at running back had the Vikings lighting up Stevan Ridley’s phone.

Ridley, the 28-year-old former Patriots running back, impressed the Vikings with his workout alongside three other running backs on Wednesday. So the Vikings signed Ridley on Thursday after placing running back Dalvin Cook on injured reserve.

The Vikings are Ridley’s sixth NFL stop in three seasons since he suffered his second torn anterior cruciate ligament in 2014 while playing in New England. The Mississippi native said he was working out and preparing for bow hunting season before he booked an unexpected flight to Minneapolis.

“It’s been tough,” Ridley said Thursday. “It’s been a lot of ups and downs, a lot of different stops, a lot of hoping and praying things work out. You never know when it’s going to be the last play. This call came unexpected. The stop before this was unexpected.”

Ridley is a depth addition for a Vikings offense that will be led by Latavius Murray and Jerick McKinnon in Cook’s absence. The former Patriots third-round pick peaked with a career-best 1,263 rushing yards in 2012, which ranked seventh in the league.

‘It’s a long season’

Tight end Kyle Rudolph isn’t fretting about the ball not finding him much through four games. A year after leading the Vikings offense in targets, Rudolph is fourth with 15 targets he’s turned into 109 yards and a touchdown, trailing Stefon Diggs (32 targets), Adam Thielen (32) and Cook (16).

“There’s a lot of things that go into targeting the tight end,” Rudolph said. “I’ve been called on a lot in protection, keeping guys on their feet. Some things, we haven’t hit them. It’s a long season. The targets and receptions will play itself out.”

Finding a balance

Coach Mike Zimmer said he can be “as moody as anybody” during a monthlong Vikings season that has swayed between big win and crushing loss in a 2-2 record. But in his fourth season at the helm, Zimmer said he’s trying to establish an emotional balance in the building akin to the steadier NFL franchises.

“I admire the teams that, whether they win 50-0 or lose 50-0, they go about their business the next week,” Zimmer said. “Really, you don’t get too high or too low.”

‘Keep going’

The Vikings are pressing forward with kicker Kai Forbath after he missed a third kick Sunday in four games this season. Forbath, an 86.5 percent career field goal kicker, hit the right upright on a 40-yard attempt against the Lions. He also missed an extra point in each of the first two games.

“I think he’s all right. We’ll just keep going,” Zimmer said. “You got to go on what you see.”

On the mend

Three Vikings — safety Andrew Sendejo (shoulder/illness), defensive tackle Shamar Stephen (back) and tackle Rashod Hill (knee) — did not practice Thursday because of health.

Quarterback Sam Bradford (knee) practiced for the first time since Sept. 21 and was limited.