Depending on which part of the country you live in, you may or may not have noticed that it's spring. For hundreds of years, scientists have used the position of the Earth with the sun to figure that out, but the more logical way is just to look around and see if college football programs are holding their spring games, and guess what?

They are.

Spring games started in force last weekend, as national champion Clemson held its game along with some other programs, but this weekend features some of the most significant teams in the country hosting their events. With so many important spring games on Saturday, now seems like a good time to go over what you should be looking for this weekend.

We'll start with the biggest name of all because that's what alphabetical order dictated.

Alabama

How does the defense look? Typically, Alabama would head into the spring with questions about its defense, but those questions would be more along the lines of "wonder what the new destroyers of worlds will look like?" Alabama has plenty of defensive turnover this season, as per usual, but unlike most years, the questions are about how a defense that allowed 78 points and 953 yards of offense in two playoff games will be in better shape this season.

We've entered a weird dimension where Alabama's offense seems to be the dominant unit, and watching its defense try to stop it on Saturday will give an early peek into how much the unit has or hasn't improved.

A look at all the new coaches. OK, so we know who Nick Saban is, but who are these new guys? A year ago at this time, Alabama was working in six new coaches on its staff. This year, it's seven. That is a lot of coaching turnover for a staff in roughly 18 months, and in a way, this spring game (and all spring practices) has been for the coaches just as much as the players.

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Auburn

The quarterback battle will be interesting. Jarrett Stidham is gone, and while Auburn pursued a few graduate transfer options over the winter, it didn't land one. The Tigers essentially have four players fighting for the spot now between Malik Willis, Joey Gatewood, Cord Sandberg and true freshman Bo Nix. QB battles are seldom settled in the spring, but Saturday could provide a glimpse of who is leading the race at the moment.

How does the run game look? Auburn's leading rusher last season was JaTarvious Whitlow, who finished with 787 yards. Now, the fact Whitlow did that as a freshman was impressive, but 2018 was also the first time Auburn finished a season without a 1,000-yard rusher since 2009. The run game has always been an essential part of Gus Malzahn's offensive attack, and with a new QB taking over, it takes on more significance in 2019. Whitlow, Kam Martin, and Shaun Shivers should all see plenty of work.

Florida

Somebody has to get the QB. Florida finished 15th in the country in its defensive sack rate last season, picking up a sack on 8.86 percent of its opponents pass attempts. However, the man who wreaked most of that havoc, Jachai Polite, is gone, and so is CeCe Jefferson. That pass rush was a major factor in Florida having such a strong season in Dan Mullen's first year while the offense was still coming along. Who will pick up the slack? One name to keep an eye on will be Jonathan Greenard. He is a grad transfer from Louisville who had seven sacks and 15.5 tackles for loss with the Cardinals in 2017, but suffered an injury in the opener against Alabama last season and missed the rest of 2018.

There's an open QB competition. Well, Dan Mullen says it's an open competition, but coaches often say every spot is open in the spring whether they genuinely believe it to be or not. Feleipe Franks is the returning starter, and last we saw him, he was leading Florida to a 41-15 win over Michigan in the Peach Bowl. He didn't have a spectacular 2018 season, but he took noticeable strides forward when compared to his freshman season. He'll be pushed by Emory Jones this spring, a four-star QB in Florida's 2018 class that redshirted last year (he did appear in four games) and some believe could be the team's QB of the future.

Miami

What will the offense look like? This is Manny Diaz's first spring as Miami's coach, and the biggest factor that helped put the former defensive coordinator in charge might have been Miami's offense last season. Or, more specifically, its lack thereof. I don't think it's a coincidence that two of Diaz's first moves after taking over for Mark Richt were to hire Dan Enos away from Alabama and help convince Tate Martell to transfer south from Ohio State. With Martell receiving a waiver from the NCAA, he's immediately eligible, and likely the favorite to win the starting job over N'Kosi Perry and Jarren Williams.

Michigan

Don't look for an actual spring game. There won't be one. Instead, Michigan will be holding an open practice, filled with individual and team drills, and what the school referred to as a "controlled scrimmage." I'm not sure what it means exactly, but I suppose we'll find out.

Nebraska

Can the Huskers stop the run? Last season was filled with ups and downs for Nebraska, but the defense was mostly down. The Huskers allowed an average of 34.3 points per game in conference play, and opponents averaged 5.0 yards per carry (5.6 in B1G play) on the season. It's going to be hard for Nebraska to take a step forward in 2018 without improvement in that area, and it's one the Huskers hope grad transfer Darrion Daniels from Oklahoma State can contribute to. Darrion joins his younger brother Damion Daniels up front.

I want a look at Wandale Robinson. With Devine Ozigbo gone, Nebraska has a hole at running back, and Robinson is a four-star recruit that was rated the No. 1 all-purpose back in the 2019 class. Nebraska lured the Kentucky product away from home and other big-name programs, and he's been compared to Purdue's Rondale Moore. Well, after seeing what Jeff Brohm was able to do with Moore, I'm very interested in seeing what Scott Frost might do with Robinson. The Big Ten West may have another highlight machine.

Notre Dame

How do the linebackers look? Notre Dame reached the College Football Playoff last season thanks in large part to its defense. A lot of key players on that defense are gone, and while that leaves questions everywhere on the unit, the Irish seem better equipped to handle departures on the defensive line and secondary. The linebacker spot is a bigger question. Both Drue Tranquill and Te'Von Coney are gone. Those two were the heart of the defense last season, and there's not a ton of proven experience behind them on the depth chart. It will be interesting to see how the Irish linebackers look on Saturday. Again, we're only talking spring games here, so there's a long time between now and when the football counts, but the linebacker position could ultimately be the deciding factor in how good the Irish are in 2019.

Ohio State

Will Urban Meyer be there? Yes, this is tongue-in-cheek, but with Meyer stepping down following last season and Ryan Day replacing him, there's still a part of me that wonders how involved or not involved Meyer will be.

Seriously, watch the QBs. The odds are good that Justin Fields will be your starter come the fall. The highly-touted transfer from Georgia likely didn't come to Columbus to sit behind another starter as he did with Jake Fromm last season. Still, the job won't be handed to him, and even with Tate Martell leaving for Miami, the Buckeyes have other intriguing options in Matthew Baldwin and Chris Chugunov. Still, this will be Fields' first chance to wow the Buckeye faithful.

Who will protect the QB? There's been so much attention focused on Fields and Day that many have overlooked the fact that nearly all of Ohio State's offensive line is gone. Thayer Munford is the only returning starter who saw regular action last season, and the Buckeyes 2019 projected left tackle has missed spring practices due to injury. This has created plenty of opportunities elsewhere, but it's also one of the team's biggest -- if not the biggest -- concerns heading into the summer and fall.

Oklahoma

Jalen Hurts, Jalen Hurts, Jalen Hurts. Did you know that Hurts transferred from Alabama to Oklahoma? Did you know that Oklahoma QBs have won the last two Heisman Trophies and that both of them transferred to Oklahoma from other schools? Will Hurts be Oklahoma's third straight Heisman winner? That won't be decided Friday night, but it will be our first glimpse of what Lincoln Riley's offense will look like with its newest signal caller.

A new look defense. There's no getting around the fact that, as successful as Oklahoma was last season, its defense was awful and held it back from being a truly elite team. That's why Alex Grinch is now running the show, and he's charged with, at the very least, taking a unit that was plain bad last season and turning it into something manageable. A few weeks of practice haven't fixed it, and it won't be fixed by Friday night, but it'll be a glimpse into the gameplan going forward.

Penn State

The QB position. Seriously, how many spring practice or spring game previews look at the quarterback position as a significant factor every year? It feels like nearly all of them, but it's because it's the most critical position on the field, and in Penn State's case, it's even more important. While he may not have been the best QB in the country, you can argue that Trace McSorley was the best QB in Penn State history.

He graduated after last season as Penn State's all-time winningest QB and holds the school records for completions, passing yards, passing touchdowns, total offense and several other categories. He was quite productive and important! Now, the Nittany Lions enter 2019 with Tommy Stevens the most likely candidate to replace him. Stevens has played a little QB while he patiently bided his time waiting for his chance (something that happens with decreasing regularity in recent years), but the job won't be handed to him. Penn State's recruited well, and Stevens will be battling with Sean Clifford and Will Levis. Taquan Roberson is also in the mix. The four-star member of PSU's 2019 class enrolled early.

Tennessee

Overhaul on the defensive line. Considering Jeremy Pruitt's background as a defensive coordinator, if he's building his program in his image, it will be a strong, defensive team. All strong defenses start on the defensive line, and as Tennessee enters 2019, it does so replacing guys like Kyle Phillips, Shy Tuttle, and Alexis Johnson. You simply aren't going to win a lot of games in the SEC without a strong defensive line, so this is a crucial area to watch for the Vols on Saturday.

Texas

Where's the pass-rush? Texas has a lot of reasons to be pleased with the way the 2018 season went. If there was a significant weakness with the team last year, however, it was a pass rush that ranked 73rd in the country in sack rate at 6.07 percent. The Longhorns had 32 sacks as a team last year, and 22.5 of them are gone with the departures of Charles Omenihu, Gary Johnson, Anthony Wheeler and Breckyn Hager. I don't know if there's a pure pass-rusher on this defense, and that's a problem in the pass-heavy Big 12. I'll be looking for somebody who could emerge as that threat on Saturday.

Taking the load off Sam Ehlinger. The Longhorns QB served as a part-time battering ram last season, and while it was effective, it's not great for your QB's health to have him running into brick walls repeatedly. So it'd be nice to see Texas show off an improved run game behind its offensive line with a running back to share that load.

Texas A&M

The offensive line. The Aggies return three starters on the offensive line, which is good. Less turnover is always better. The problem is one of the departures was center Eric McCoy, who started the last three seasons and was an absolute rock on the unit, as well as its leader. I would expect to see some bumps in the road as the Aggies look to replace a player so pivotal to the most important unit on any offense.