The past two seasons have been rough for the Missouri Tigers, who reached the SEC Championship Game in 2013 and 2014. (The good days aren’t too far gone, Mizzou fans!)

In 2015, Mizzou went 5-7 in legendary coach Gary Pinkel’s final season and, in 2016, the Tigers finished 4-8 but ended the year with an inspiring come-from-behind victory over Arkansas.

Heading into this offseason, the Tigers need to make some difficult roster decisions in order to avoid another disappointing campaign in 2017. Important players must be replaced and unknowns must step up into featured roles if the team is going to claw its way back to bowl eligibility.

From the backup quarterback position to tight end to pass rushers, there are plenty of spots that need to be filled.

Here’s a quick look at five important roster questions that must be answered before the 2017 season kicks off in September.

Who will back up Drew Lock?

This year’s backup quarterback, Marvin Zanders, plans to transfer, leaving the Tigers without an obvious backup for Drew Lock.

Junior Jack Lowary is the oldest of the remaining quarterbacks, so it’s possible he could fill the role, but freshmen Hayden Rymer and Micah Wilson are on the roster, too, and will have a chance to show what they can do in spring practices.

Reyondous Estes, a three-star dual-threat quarterback, will be a part of head coach Barry Odom’s 2017 recruiting class, so he could find himself in the backup mix as well.

How will the running backs split time?

Damarea Crockett burst onto the scene and will enter the 2017 season as one of the SEC’s most dangerous running backs.

However, Ish Witter, who will be a senior, has proven he deserves his fair share of carries. Then there’s Nate Strong, who finished last year on a high note.

Crockett figures to be the starter after rushing for 1,062 yards and 10 touchdowns, and Witter deserves to be his backup. That leaves Strong, who showed his skills by rushing for two touchdowns in the come-from-behind victory over Arkansas in Crockett’s absence.

Having three talented backs in the mix is certainly an enviable problem to have, but offensive coordinator Josh Heupel is still going to have to figure out how the rotation will work to keep everyone happy.

Which tight end will be No. 1?

Sean Culkin led all Mizzou tight ends with 24 catches for 282 yards last year, but the senior failed to find the end zone.

Sophomore Kendall Blanton, on the other hand, only had 16 catches for 161 yards, but managed to score three times. Junior Jason Reese added eight catches for 97 yards with two touchdowns.

Blanton and Reese will split the tight-end duties in 2017, but the Tigers need more from the position if they’re going to have more success. Whoever emerges as the starter needs to put up more than last year’s combined totals of 48 catches, 443 yards and five touchdowns in Heupel’s high-flying offense.

Who will replace Aarion Penton and John Gibson?

Aarion Penton led the SEC with five interceptions heading into the bowl season (Alabama’s Minkah Fitzpatrick has since surpassed him with six) and John Gibson snagged three more picks for Mizzou’s opportunistic secondary.

Replacing those two outgoing seniors will be a top priority for DeMontie Cross, who disappointed in his first season as Mizzou’s defensive coordinator, overseeing one of the biggest season-long defensive collapses in all of college football.

The Tigers’ pass defense struggled as a whole last year, so Cross should make sure he has the right players to fit into whatever scheme he wants to employ in the secondary in 2017, even if said players are not the ball-hawks Penton and Gibson were.

Who attempts to fill Charles Harris’s shoes?

Charles Harris may have gotten off to a slow start last season, but he still finished with nine sacks and two forced fumbles. The junior declared for the NFL Draft after the season, though, so now the Tigers are left with a huge hole in their pass rush.

Finding the next potential first-round pass rusher will be of vital importance for the Mizzou defensive line.

Unfortunately, talented DT Terry Beckner Jr. tore his ACL late in the 2016 season and will likely miss spring ball. Still, DE Marcell Frazier, a rising senior, showed some promise at the end of the year, recording 6.5 sacks in his final three games and finishing the year with 7.5.

If Frazier and Beckner can take another step toward stardom in 2017, the loss of Harris may not be as devastating as it seems now.