Oklahoma State surprised in 2015, reaching double digits in wins for the fourth time in six years, finishing 10-3.

Nonetheless, the Cowboys finished the year with three straight losses, looking overwhelmed and out of sorts in losses to Baylor, Oklahoma and Ole Miss. Several critical pieces return, particularly quarterback Mason Rudolph and receiver James Washington, but other key players, such as Kevin Peterson, are moving on. Mike Gundy's program will have plenty of questions about the future heading into the offseason.

Here are five questions for Oklahoma State heading into the 2016 season.

Can the Cowboys take the next step?

Mike Gundy’s program sits tied with Notre Dame and Louisville with the 14th highest win percentage in FBS during the past five seasons (72.3), ahead of TCU, Kansas State, USC and Texas A&M among others. Yet the Cowboys have just one Big 12 title to show for it (2011) and saw Bedlam losses to Oklahoma ruin their Big 12 title hopes in 2013 and 2015. Oklahoma State has accomplished its goal of building a consistent championship contender. Now the Cowboys need to win another Big 12 title and stop allowing title chances to go down as missed opportunities, even though that’s much easier said than done.

Will the offensive line ever get fixed?

It’s been two years since Joe Wickline left Stillwater, Oklahoma to join Charlie Strong at Texas. At some point this problem needs to be solved. During the past two seasons, Oklahoma State averaged 131.4 rushing yards per game, 3.54 rushing yards per carry, 67.1 rushing yards before contact per game and 1.81 yards before contact per carry, according to ESPN Stats and Information. During the previous four seasons, with Wickline tutoring the offensive front, the Cowboys averaged 179.7 rushing yards per game, 5.01 yards per carry, 77.4 rushing yards before contact per game and 2.85 yards before contact per carry. The bottom line is Oklahoma State has been unable to run the ball since Wickline left. And until it can, its Big 12 title dreams might be unrealistic.

Can they replace the stars on defense?

Star defensive end Emmanuel Ogbah hasn’t officially announced plans to leave early for the NFL draft, but the fact he took part in Oklahoma State’s senior day speaks volumes. Cornerback Kevin Peterson and defensive end Jimmy Bean definitely are out the door, so Gundy’s program has some work to do to replace some key playmakers. There is young talent on the roster at defensive end and cornerback, but replacing NFL-level talent never is easy.

What happened to the running back tradition?

The running back room was overflowing with talent at Oklahoma State in 2010 when the Cowboys had two NFL backs (Kendall Hunter, Joseph Randle) and a top-notch third option (Jeremy Smith). The Cowboys haven’t had a 1,000-yard rusher since Randle left in 2012. Worse yet, the leading rusher has gained fewer yards each season, culminating in Chris Carson’s 517 rushing yards in 13 games this season. Major misses on the recruiting trail -- Ronald Jones’ decommit and no Plan B along with Devon Thomas’ off-field issues -- have helped land the Cowboys in this spot. Oklahoma State recruits and evaluates too well to have such a void at running back for three straight years.

Can Rudolph-to-Washington become the next Weeden-to-Blackmon?

Oklahoma State’s only Big 12 title was built upon the shoulders of an unstoppable quarterback-receiver duo in 2011. Brandon Weeden and Justin Blackmon were a handful for Big 12 defenses, and the Cowboys should be hopeful Mason Rudolph and James Washington can take their connection to the next level in 2016. Oklahoma State’s offense was considerably more explosive when Rudolph and Washington were clicking, with the duo connecting 53 times for 1,087 yards and 10 touchdowns as sophomores. They'll return as experienced juniors in 2016, which could mean another jump in production.