GREEN BAY — In the weeks leading up to the 2015 NFL Draft, the St. Louis Rams asked running backs coach Ben Sirmans to check out this 6-foot, 220-pound receiver from Stanford.

The coaching staff and personnel department was curious whether the receiver had the potential to convert to running back, so Sirmans went to work. He pulled up the tape and began taking notes.

It was here that the future Packers running backs coach was first introduced to his future pupil, Ty Montgomery.

“Obviously, I didn’t feel like I had enough footage on him to make a great decision from that,” Sirmans said. “But I do remember looking at him as a guy we could potentially draft as a third-down back.”

The Packers drafted Montgomery in the third round as what west regional scout Sam Seale touted as a bigger Randall Cobb, a hybrid who could line up either as a receiver or in the backfield.

Montgomery played here and there through his first year until Packers Head Coach Mike McCarthy finally approached him earlier this season to take his temperature on possibly working with Sirmans in the running backs room.

Montgomery jumped at the idea and Sirmans was more than happy to take on another challenge. Getting players up to speed has been the norm for the former high-school health teacher since the Packers hired Sirmans to coach their running backs in February.

Sirmans has worked with 13 different running backs and fullbacks since the start of organized team activities, including former Newberry (S.C.) College defensive lineman Alstevis Squirewell.

“It’s been different. I’ve never had to experience a situation like this where I’ve had so many different guys in and out,” Sirmans said. “Shoot, we were talking about it before – the guys I had in training camp to the guys I have in my room a few weeks ago was only a handful. It’s all part of the job.

“No matter who you have coming in the room, you expect for that person to perform well enough for you to be successful. So that’s how I approach it. I have to make sure this guy is going to be successful.”

The biggest storyline over the summer was how Sirmans could help Eddie Lacy get back on a Pro Bowl track after a down year in 2015, and to a certain extent, he did.

Lacy was off to the best start of his career with 360 rushing yards on 71 carries (5.1 yards per attempt) before an ankle injury ended his season after only five games.

That’s when the carousel began for the Packers’ backfield. With James Starks also out with a knee injury, Green Bay’s personnel department worked quickly to restock the backfield.

Over the next month, Knile Davis was acquired in a trade with Kansas City, Don Jackson was promoted off the practice squad and Christine Michael was later claimed off waivers.

All three pulled early-morning and late-night study sessions with their new coach. At the same time, Sirmans was working non-stop with Montgomery to teach the nuances of the position.

“He’s done an outstanding job,” said offensive coordinator Edgar Bennett of Sirmans. “You look at the different guys who have come into that room and getting those guys prepared, and the time and effort he puts into it. Every spare moment, he’s down there in that room and bringing those guys to where they need to be in order to put themselves in position to help us on the field.”

Sirmans has never had an in-season project quite like Montgomery, but he had some experience working with hybrid players. In St. Louis, Rams receiver Tavon Austin would occasionally pop into Sirmans’ meetings for certain packages.

Austin (5-8, 176) carried the ball 97 times for 809 yards and seven touchdowns under Sirmans’ tutelage, the most backfield activity by any NFL receiver over the past three seasons.

While Montgomery is substantially larger than Austin, many of the same lessons apply. From Sirmans’ perspective, it also helped that the Stanford grad was exceedingly eager to learn the position.

Each time Sirmans walks into the room, he knows Montgomery is likely to ask the most questions and it’s translated on the field with 829 all-purpose yards (228 rushing, 313 receiving and 288 kickoff returns) this season.

“I think the biggest thing he’s brought besides still learning some things about the running back position is utilizing his skill set as a receiver,” Sirmans said. “He has an understanding of the pass game that other guys don’t; the grasp of all the concepts like he does. I think that helps make him more valuable for us.”

Along with overseeing Montgomery’s conversion, perhaps the greatest tribute to Sirmans’ work has been the fact the Packers have had five players (Michael, Jackson, Davis, Jhurell Pressley, and fullback Joe Kerridge) take offensive snaps this season despite not being with the team during training camp.

Sirmans also has been in charge of Aaron Ripkowski taking the reins as the Packers’ starting fullback. The former sixth-round pick, who spelled John Kuhn last season, has been effective as a lead blocker, pass protector and even ball carrier at times this season.

His players feel Sirmans’ teaching style works because he creates an environment in the running backs room that his players feel makes it easy to absorb the system and contribute quickly.

“I love Coach Sirmans. I think he’s a great coach,” Montgomery said. “We have a really good relationship and he’s been crucial to helping me understand things, staying late, and coming early in meetings to make sure I understand some things because I had to learn this stuff really fast on the fly.”

McCarthy made Montgomery’s move to running back official earlier this week and the Packers likely will put all of his work with Sirmans to the test over the last three weeks of the regular season.

There have been some late nights this season, but Sirmans wouldn’t have it any other way.

“It’s been a new situation for me,” Sirmans said. “Being a teacher prior to coaching, one of the things that you do learn is you have to teach all different types of people with all different types of ability to learn. Having different guys pop in and out of the room based on my experiences, I don’t want to say (it’s) gratifying but it is something I do enjoy getting guys ready and enjoy that challenge.

“Obviously if they perform at a high level, it makes me feel even better from a teaching standpoint.”