He knew the position he was taking over had multiple veterans with playing experience, but how they would fit in with the new offensive scheme being installed by Mark Stoops and Neal Brown remained to be seen.
Eight practices into the spring, much of that mystery is gone.
"The surprise to me is Jordan Aumiller," Marrow said. "He looks like a guy that you can really line up with and do some things with. He's a big 6(-foot-)5, 6-6 guy that can run with soft hands."
After seeing his playing time dwindle since an impressive freshman season, Aumiller - a senior - began the spring playing on the third string. Now, he's played his way onto the first string.
And Aumiller isn't the only one who has impressed.
"(Aumiller) and Tyler Robinson (who has dropped 15 pounds this offseason) were supposed to just be blockers," Marrow said. "Those guys have established themselves as some good pass-receiving tight ends."
UK's tight ends combined for just 18 catches for 165 yards last season, but the arrival of a new offense meant that production was likely to increase significantly. After all, Texas Tech's top tight end in 2012 - Jace Amaro - caught 25 passes for 409 yards and four touchdowns in just seven games. However, it's not as if UK's tight ends will be completely eschewing their roles in the running game.
"I evaluate my guys like I was coaching pro guys," Marrow said. "I want a guy that can do both. You want to start off making him a blocker, but in this offense you want a guy who can catch."
The need for UK's tight ends to be threats in the passing lane has only grown this spring as it's become clear just how much work the wide receivers have ahead of them. For that reason and the nature of Brown's offense, a few players listed as tight ends are playing hybrid roles in practice. Returning junior Ronnie Shields and junior-college transfer Steven Borden have the size and versatility needed to create matchup problems no matter where they line up. Senior Anthony Kendrick could do the same when he returns from injury.
"Ronnie Shields has done a good job," Brown said. "We are playing him a little more standing up. Steven Borden has done a nice job. He has a good skillset that will match well with what we want to do."
Borden was the first player of the Stoops era to commit to UK, so it makes sense that he fits so well in Brown's system. The Waxahachie, Texas native has played anywhere from tight end to the slot to fullback, but the two seasons he spent at Kilgore College helped him prepare for that.
"At my last junior college, I moved around a bunch too," Borden said. "So I knew in this offense the tight end and slot receivers can be similar sometimes. I knew coming in there was a chance I was going to be flopping around a little bit. I didn't know I was going to be in at fullback."
Considering he's only just learning a brand new offense, moving around so much has put a lot on Borden's plate this spring. He doesn't mind.
"I like it," Borden said. "I like being challenged."
Borden hasn't even played a Division I down yet, but he might already be the most high-profile tight end on UK's roster. His visit to campus and eventual commitment generated interest among fans because of his father and namesake, Steve Borden. Borden is better known as his professional wrestling persona - Sting.
"I always tell people he's been a wrestler since I was born, so I don't know anything different," Borden said. "To me, I feel like I had a fairly normal childhood. He came and watched me play football and went to school, did things that pretty much every other kid does. I don't know anything different."
For many offspring in the wrestling community, it becomes a family business, but not for the UK tight end. Borden has always been encouraged to make his own name.
"For me, I want to do my own thing," Borden said. "I'm proud of my dad and I think he supports me in what I do."
What Borden is doing now is going to school and competing for playing time at tight end. Along with quarterback, Brown said the position was the most crowded on the offense. The good news, however, is that there's nothing in the rulebook that says only one can play at a time.
"We are going to figure out - and I am in the process and it might take until we get into fall camp a week or two in - but we have to figure out who we are, who are our best 11 and then who are next best skill guys are," Brown said. "It is a work in progress. Right now, I would say, you may see one or more of those guys on the field a lot."