The East semifinal's most compelling storylines

With the regular season over, the CFL's first-round playoff matchups are all set for this coming Sunday. The B.C. Lions will cross over to the East Division to face the Montreal Alouettes in one divisional semifinal (1 p.m. Eastern), while the Edmonton Eskimos will host the Saskatchewan Roughriders in the West semifinal (4:30 p.m. Eastern). Both games should be exciting, and there are plenty of intruiging storylines ahead of each. Here's a look at the top storylines in the East. (See also our look at the top storylines in the West.)

Hot and cold: Both of these teams finished with 9-9 records on the season, but they got there in different ways. Montreal got off to a horrendous 1-7 start and was described as hitting "rock bottom", but some high-profile coaching changes, the benching and eventual release of Troy Smith, the at quarterback and the defence returning to the elite form it displayed last year helped the Alouettes turn things around. They won six straight games down the stretch and were in place to take the East Division title before losing their final game to Hamilton Saturday. Meanwhile, the Lions got off to a somewhat better start, but have had up-and-down peaks all year. They enter the playoffs on a two-game losing streak, and they're in the East thanks to dropping their final game to a Calgary team with nothing to play for Friday. They'll need to improve dramatically if they want to keep their hopes of reaching a home Grey Cup alive.

A clash of defences: On the season, Montreal allowed 394 points, best in the East Division and fourth overall in the league. B.C. conceded just 365, third-best overall. These teams allowed the third- (B.C., 315.9) and fourth- (Montreal, 324.1) lowest yards against per game. However, they did so in different ways. The Lions are terrific against the pass, allowing just 7.2 yards per pass and a 60 per cent completion mark (both second-best in the league), plus the third-lowest passing yards against per game (225.9), but vulnerable against the run. They allowed 5.8 yards per rush, third-worst in the league. Meanwhile, the Alouettes are strong against the ground game, allowing 5.2 yards per carry (third-best in the league), but weaker against the pass; they gave up a league-high 64.4 per cent completion percentage and 7.5 yards per pass, fourth-worst. We'll see which of these vaunted defences can do more Sunday.

Unexpected quarterbacks: Neither team imagined at the end of last year that they'd be using their current starting quarterback. Montreal made a late-season run to the playoffs with Smith, who looked like the heir apparent to Anthony Calvillo, while Travis Lulay was under centre as normal for the Lions in their postseason appearance. Both teams lost in their respective semifinals last year, but both losses were close, and both teams appeared set at quarterback heading into this year. Lulay's offseason shoulder surgery took more time to heal than expected, though, persuading the Lions to trade for Kevin Glenn at the draft and use him to start the season, and when Lulay went down again midway through the year in his attempted return, Glenn took the controls again. Meanwhile, Smith struggled early on with Montreal, and was benched in favour of Crompton (who was only signed as a free agent in July following his release by Edmonton). The second-year CFL man out of Tennessee wound up making the position his own down the stretch. Neither of these quarterbacks was an expected starter, but both have been quite good at times. We'll see who's more effective Sunday.

Unusual top players: The most typical team nominee for most outstanding player is the quarterback, but that isn't the case for either of these teams. In B.C., it's linebacker Solomon Elimimian, who shattered the CFL's tackle record with 143 this year. (Notably, his next highest competitor was Calgary's Brandon Smith with just 85; Montreal LB Bear Woods tied for third with 80.) Elimimian also recorded five sacks, three fumble recoveries and an interception. In Montreal, the team nominee was wide receiver Duron Carter, who finished fourth in the league and first on the team with 987 receiving yards. He also had six touchdowns on the season. Which one of these stars shines brighter Sunday may determine a lot about this game.

Master meets apprentice: Montreal kicker Sean Whyte started his career as Paul McCallum's backup in B.C., but the Lions eventually traded him to the Alouettes at the 2012 draft. Whyte's since gone on to shine in Montreal, while McCallum is still doing well in B.C. at age 44. McCallum has made 90.5 per cent of his field goals this season, best in the league, and is fifth in the CFL with 150 kicking points, while Whyte has hit 86.4 per cent of his attempts (fifth-best) and is sixth with 145 kicking points. Whyte has averaged 44.9 yards per punt this year, sixth-best in the league, while B.C. punter Ricky Schmitt is eighth with a 44.5 yard average. It's going to be interesting to see if Whyte can outduel the guy he used to train under.

(Correction: This piece initially had Hugh O'Neill as B.C.'s punter. He was their punter in 2013 before being traded to Edmonton. B.C.'s punter now is Ricky Schmitt. Thanks, Gord!)