The dreaded sophomore slump can strike without warning. It is widely assumed that rookies will improve with experience, but that is not always the case. Whether it's a change in usage, a new coaching staff, stiffer competition or simple regression, a player may not match the expectations raised by their rookie performance.

Here is a look at five players from the 2015 draft class who may not live up to higher expectations entering the 2016 NFL season. Average Draft Position Data is according to Fantasy Football Calculator 12 team Standard ADP as of May 12th.

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Sophomores Who May Slump in 2016

Stefon Diggs (WR, MIN, ADP: 9.05)

Diggs was one of the most pleasant surprises among rookies at the skill positions in 2015. He caught 52 passes for 720 yards and four touchdowns in only 13 games, making for a popular in-season addition for fantasy owners active on the waiver wire. Most of Diggs' damage came between weeks 4-8, when he accumulated 419 yards in four games. After week 8, his production fell off and he only recorded more than four receptions in a game once. His decrease in production could be attributed to opposing defenses identifying him as the primary target for Teddy Bridgewater in the Vikings offense.

In April, the Vikings spent a first-round pick on Ole Miss Wide Receiver Laquon Treadwell and sixth-rounders on German Wide Receiver Moritz Bohringer and UTSA Tight End David Morgan. The addition of the incoming rookies will limit the numbers of targets that Diggs will see. Even if he starts opposite Treadwell, it is unlikely Diggs will be putting up 100 yard games. Minnesota will continue to be a run-first offense with Adrian Peterson, so big receiving games will be few and far between. With more receiving threats on the roster, Diggs won't be higher than a WR4 this season in fantasy football leagues.

Devin Funchess (WR, CAR, ADP: 13.01)

A 31-473-5 line and a 13th round ADP might seem like an easy bet to live up to, but Funchess will be dealing with more than the possibility of a sophomore slump. As amazing as Cam Newton was, coming off of a Super Bowl loss, the chances of him matching his MVP season are slim. Even if Carolina's passing game manages to come close to last year's production level, there is also the fact that fellow big wide receiver Kelvin Benjamin will return to the Panthers lineup after missing all of 2015 with a torn ACL.

The 6'5", 245-pound first-rounder from FSU will take over as the top WR target, followed closely by TE Greg Olsen. This leaves Funchess as the third option at best. Additionally, Newton tends to spread the ball around evenly, so it's hard to envision too many breakout performances with veterans Ted Ginn and Corey Brown still around. Funchess will not help fantasy owners and is nothing more than a late-round flyer.

Duke Johnson (RB, CLE, ADP: 8.03)

There is no debate Duke Johnson is fast. The 5'9" speedster regularly ripped off big runs at Miami and is a threat catching the ball out of the backfield. One might think this would lead to big play ability, but that wasn't on display in his first season with Cleveland. His longest run was 39 yards and he only averaged 23.7 rushing yards per game. The opportunity was there for the taking, with only Isaiah Crowell standing in his way, however, Johnson never became the Browns full-time starter.

I expect Johnson's role to stay the same - he will be an outlet receiver on obvious passing downs and an occasional change of pace back. His injury history in college is a cause for concern in regards to any increased workload. Johnson's great hands and breakaway speed give him potential value as a flex for deep leagues in PPR formats, but chances are his fantasy value will continue to be limited.

Jeremy Langford (RB, CHI, ADP: 3.10)

When Matt Forte went down in week 8, Langford took over as the primary back for Chicago. In Adam Gase's offense, he was asked to catch the ball out of the backfield regularly and served well in that role. Langford produced 142 combined yards in week 9 and had a 100-yard receiving game in week 10 to go along with 73 rushing yards. Just when he was looking like a waiver wire revelation, his production came back down to earth. Langford didn't reach 70 total yards in any of the next five weeks, and he didn't surpass 83 combined yards in the last 7 weeks of the season. In a timeshare with Forte, his role diminished and he failed distinguish himself as a lead back.

Langford's 3.6 yards per carry is likely one of the reasons the Bears pursued C.J. Anderson in free agency. Even with Forte now wearing a Jets uniform, Langford won't necessarily become a feature back in Chicago. Ka'Deem Carey and Indiana Rookie Running Back Jordan Howard could carve out roles and I wouldn't be surprised if the Bears look to add a veteran in free agency during training camp either. Langford has talent, but his two week breakout last season may have been more fluke than predictor. Langford projects as a low-end RB2 for this coming season, which makes his 3rd round price tag unpalatable.

T.J. Yeldon (RB, JAX, ADP: 7.06)

T.J. Yeldon, meet Chris Ivory. The Jaguars invested $32 million over 5 years to make Ivory a big part of the offense. It's hard to envision the coaching staff having much faith in Yeldon beyond a third-down back role if they felt compelled to sign a free agent running back to such a large contract. Yeldon posted respectable numbers during his rookie campaign, averaging 4.1 yards per carry, totaling 740 rushing yards and 279 receiving yards. PPR leagues may have use for Yeldon as a deep reserve, since he should produce similar receiving numbers, but his rushing numbers are sure to decline significantly.

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