MSU guards Gary Harris and Denzel Valentine have not been immune to it.

After starting the year as two of the more impressive freshman guards in the Big Ten — talented enough to earn starting roles and Big Ten freshman of the week honors in December for Harris — both players appear to be in the middle of slumps.

Having witnessed first-year players crash into the methodical freshman wall time and again, head coach Tom Izzo said it’s a period many players are forced to battle through.

“It’s like when I ran a marathon once and everybody told me the 20-mile mark is when you hit the wall,” Izzo said. “I got to 20 miles and I felt pretty good. I said that wall theory is out the door.

“The 21-mile mark, my face started going numb, you know. Some guy who was 80 (years old) passed me and I knew I was in trouble.”

After close to 75 practices and more than 20 games, including exhibitions, for the No. 13 Spartans (16-3 overall, 5-1 Big Ten), Harris and Valentine have showed varied degrees of struggle in January.

Valentine has just six total points in his last four games and has had a tough time making an impact against Big Ten opponents. Still, the Lansing native remains second on the team in assists (2.7 per game) and fourth in rebounds (4.2 per game), having played in all 19 of the team’s regular season games.

Searching for more consistent production from his starters, Izzo recently replaced Valentine in the starting lineup with junior center Adreian Payne, while still getting Valentine 18 minutes on the floor in Saturday’s win against No. 14 Ohio State.

“It was kind of hard on Denzel because he’s a freshman,” sophomore guard/forward Branden Dawson said. “He kind of hit that freshman wall but you know, he’s just adjusting and seeing from the bench what he needs to do when he goes in the game.”

Harris is a different story, as he leads all Big Ten freshmen in scoring with 12.6 points per game. The 6-foot-4, 205-pound Harris has faced multiple shoulder injuries this season and it appears to have affected the flow of his shot, noticeable in a 37.3 shooting percentage in the month of January.

However, Harris said he doesn’t believe he’s hit a wall.

“No, I don’t really buy into it,” Harris said after the game on Saturday. “(Izzo) said every freshman hits the wall, but I feel like I haven’t hit it yet so I’m going to keep playing.”

During his weekly press conference Monday, Izzo said both players understand the writing on the wall and are working toward resolving a midseason slide.

With a pair of challenging road games facing the Spartans this week against Wisconsin on Tuesday before traveling to meet No. 7 Indiana on Sunday, Izzo said he expects both players to make a comeback.

“In my time, I’ve seen freshmen struggle a little bit but as tough as both of them are, I have no qualms they’ll bounce back,” Izzo said.