8 Storylines to Watch out for as the Champions League Resumes
The long wait for the return of the UEFA Champions League is almost over, as the knockout round begins on Tuesday in Manchester and Leverkusen.
As the Round of 16 begins, there are plenty of juicy storylines surrounding each of the teams left in the prestigious competition.
Continue reading for a look at the eight storylines you should watch out for as the Champions League resumes.
Manchester City's Quadruple Quest
Manchester City are still alive in four competitions this season (FA Cup, Capital One Cup, Premier League and Champions League) and they have a legitimate chance of winning all four trophies.
But manager Manuel Pellegrini insists his players are not focused on such things.
"We never talk about (the quadruple)," Pellegrini said, per Yahoo! Sport. "We try to fight in all the competitions as far we can. It is one step more but we continue now in Champions League."
City's biggest challenge outside of the Premier League presents itself in the form of Barcelona in the Round of 16. The good news for Pellegrini's men is that they get to start the two-legged tie off at the Etihad Stadium, a stadium that they have made a fortress in recent years.
If the Citizens can put up a few goals on Barcelona's shaky defense at home, it could give them the momentum to pull off a big win at the Camp Nou in the second leg on March 12.
Manchester United and AC Milan Look to Salvage Disappointing Seasons
Two great European powers, AC Milan and Manchester United, are in the middle of seasons that will currently not see either qualify for European competition next season.
One way for the two troubled clubs to get back on track is to win in the round of 16 against Atletico Madrid and Olympiakos, respectively.
Clarence Seedorf will guide the Rossoneri into a European match for the first time on Wednesday at the San Siro against Atletico Madrid. A win in that match would do wonders for the confidence of a team stuck in 10th place in Serie A.
A victory in the first leg would be exactly what the doctor ordered for David Moyes' Red Devils as well since the club are in seventh place in the EPL.
It is worth noting that the Red Devils will be a well-rested side heading into their clash on February 25 with the Greek champions because they are not involved in any of the domestic cup competitions.
Atletico Madrid's Chance to Extend Continental Success
Atleltico Madrid have been a dominant power in the UEFA Europa League in the last few years with two titles in 2010 and 2012, but this season, they are looking to translate that success into a long run in the Champions League.
The leaders of La Liga will have a chance to make a leap forward in their European progression against a struggling AC Milan side in a tie that begins on Wednesday at the San Siro.
Diego Simeone's men have shown no fear on both the domestic and continental levels this season, and the showdown with AC Milan presents a chance for them to announce to the rest of Europe that La Liga is no longer a two-team league.
With in-form goalscorer Diego Costa in the lineup, Los Colchoneros have the capability of scoring plenty of goals while also boasting a fine young keeper in Chelsea loanee Thibaut Courtois.
Messi's Chase of Raul
The next record that Barcelona star Lionel Messi is set to break is the one Raul currently holds as all-time leading scorer in Champions League history.
Messi is six goals behind Raul's 71, and if the Catalans go on a rampant run through the knockout round, he could break that record before the season ends.
The first opponent in Messi's path will be Manchester City, a team that are certainly susceptible to conceding on the road, but not so much at home.
If Messi can shine in the second leg at home and pull off a solid day on the pitch in Manchester on Tuesday, he could be well on the way to breaking the Spanish legend's record further down the road in the knockout phase.
Zlatan Ibrahimovic's ego must love the fact that we are devoting an entire slide to him.
The Paris Saint-Germain forward will not be making the trip to Brazil for the 2014 FIFA World Cup this summer, so his last chance to attain glory this season comes in the Champions League. As noted by Squawka Football, he is one of the tournament's most dominant scorers.
Last season, PSG were taken out in the quarterfinals by Barcelona on away goals. This year, Zlatan and his teammates will look to get past that stage as they search for the first French Champions League title since Marseille in 1993.
The Parisians will open their knockout stage campaign at the Bay Arena against Bayer Leverkusen on Tuesday night, a match where Zlatan will surely find his way onto the scoresheet.
Didier Drogba Faces Mourinho's Chelsea
In any other year, a clash between Chelsea and Galatasaray would not be feared by fans of the London club, but because of a former club legend's presence, a bit of fear has set in.
When the two sides clash for the first time on February 26, Didier Drogba could line up against the club and manager that brought him a treasure trove of success during the prime of his career.
While there is a ton of respect between Drogba, Jose Mourinho and the whole of Chelsea Football Club, the motivation for the Ivorian to score, and potentially win, against his former club has to be high.
Surely there will be some sentimental exchange between both sides at the start of the match, but in all reality, Galatasaray are a dangerous team that Chelsea must not fall asleep on.
It is worth remembering that the Turkish side handed Real Madrid a serious challenge in last season's quarterfinals before falling to Los Blancos on a 5-3 aggregate.
Pep vs. Arsene
Two of the most successful managers in recent world football history will square off against each other in the Round of 16 when Pep Guardiola's Bayern Munich face Arsene Wenger's Arsenal.
Guardiola has won two and drawn one of his four career matches against Wenger in the Champions League, with Wenger only coming out on top once.
Wenger's lone win against the Spanish mastermind came in the first leg of the Round of 16 back in 2011 when the Gunners won 2-1 over Barcelona before losing the second leg, 3-1, and dropping out of the competition.
The Gunners have not won a major trophy since 2005, and for Wenger to get over that hump with his team, he must take a down a foe that has gotten the best of him for the most part.
For Arsenal to beat Bayern at home on Wednesday, they must play strong at the back and then hope that Olivier Giroud can convert on a chance or two in front of goal, which is something he only did twice in group play.
Will Anyone Break the Spanish and German Dominance?
Last season, all four of the semifinalists came from Spain and Germany, with the Bundesliga duo of Bayern Munich and Borussia Dortmund taking down Barcelona and Real Madrid in the final four of the competition.
As the Round of 16 begins, there are five legitimate title claims to be made by teams from the two countries. Of the seven clubs from Spain and Germany left, only Bayer Leverkusen and Schalke are not considered favorites to win it all.
As long as the major powers from both nations do not face off in the next round as well, we could end up with another final-four showdown to determine who faces off in Lisbon on May 24.
While that has a strong possibility of happening, the four English clubs and PSG will look to make sure this doesn't become a yearly trend in the Champions League.
Follow Joe on Twitter @JTansey90.