By Stephen Johnson–

(670 The Score) “Sit ‘Em, Start ‘Em” is a breakdown of some of the best and worst fantasy football matchups to help you navigate setting your lineups for the week.

It’s league semifinals week, and if you survived without Rob Gronkowski, a limited Alvin Kamara or an inefficient Tom Brady, hopefully luck is on your side heading into another big matchup. Major shakeups to the fantasy landscape loom in Week 15 with the return of Packers star Aaron Rodgers and a disastrous knee injury that figures to impact the Eagles’ chances of securing home-field advantage heading down the stretch.

Quarterback

START – Blake Bortles, Jaguars (vs. Texans) There’s nothing like having your season on the line and watching your fantasy quarterback go down with a season-ending injury like many Carson Wentz owners did this past weekend. Luckily for them, they can turn to … Bortles? It’s hard to say anyone could’ve seen this possibility coming with semifinal weekend upon us, but Bortles happens to be one of the hottest passers over the last three weeks, averaging 22 points per game. As for his opponent, the Houston Texans, they’ve had a disaster of a season. The Texans have allowed the fifth-most passing touchdowns and rank 30th in 4for4’s quarterback aFPA (schedule-adjusted fantasy points allowed). Houston offers up a matchup that not only makes Bortles a top waiver option but also a strong threat to put up QB1 numbers this week.

SIT – Alex Smith, Chiefs (vs. Chargers) Smith’s home-and-away splits are some of the most bizarre of the 2017 season. Kansas City has been struggling for the past several weeks but specifically at home, where Smith averages 243 yards passing compared to 292 yards away from Arrowhead. This week is a must-win for the Chiefs, and the task at hand isn’t an easy one against the Chargers, who have allowed the fewest points to the position over the last month thanks to their menacing secondary led by Casey Hayward.

Running back

START – Christian McCaffrey, Panthers (vs. Packers) Although Green Bay’s defense has faced the second-most rushing attempts in the league, it has managed to hold opponents to a 3.94 yards-per-carry average. Dealing with pass-catching backs is another story however, as the Packers have allowed the most receiving yards over the last four weeks at 70 yards per game. Enter McCaffrey, whose 67 receptions place him 14th among all players in the NFL. The elusive McCaffrey’s production has decreased in recent weeks, as he has touched the ball nine or fewer times in three of his last five games. Expect that to change however, as the Packers have surrendered 81 receptions to the position this season.

SIT – Orleans Darkwa, Giants (vs Eagles) Philadelphia’s run defense has continued its dominant path to the top of the league ranks, allowing just 650 rushing yards to running backs this season, an average of just 50 per game. Darkwa’s tenure as the Giants’ lead back may be nearing its end as rookie Wayne Gallman eclipsed him in carries last week by a count of 12-10. Last week’s split comes on the heels of a three-week stretch in which Darkwa has averaged 30 yards on the ground.

Receiver

START – Dede Westbrook, Jaguars (vs. Texans) Last year’s Fred Biletnikoff Award winner, Westbrook is finally getting the attention he deserves, and it just so happens to come at the most important time of the season. Westbrook comes into this game as WR14 over the last two weeks and is facing a Texans secondary that has been torched by speedsters this season. Apart from J.J. Nelson, the five other wideouts who had a 4.40 40-yard combine time or better have averaged six catches, 128 yards and a touchdown against Houston this season. Westbrook’s 40 time? 4.34.

SIT – Robby Anderson, Jets (at Saints) Anderson’s breakout season has him on pace for a 1,000-yard campaign in New York, but a slight change of cast combined with a difficult defensive matchup is going to make Week 15 difficult. Bryce Petty gets the start at quarterback this weekend for the Jets, sporting a career 57.9 passer rating and 3:7 touchdown-to-interception ratio. Meanwhile, Anderson will have to deal with rookie standout Saints cornerback Marshon Lattimore, who allows the fifth-fewest fantasy points per route among all eligible players.

Tight end

START – Jack Doyle, Colts (vs. Broncos) The bizarre narrative that is the Broncos’ passing defense continues this season, as it allows the second-fewest passing yards but the most touchdowns through the air. Most of the damage has come via opposing tight ends, who have dominated Denver away from the Mile High City, putting up 16 points per game in PPR leagues. Adding insult to injury, only two teams have allowed more TE1 games than the Broncos this season.

SIT – Tyler Kroft, Bengals (at Vikings) The Vikings’ defense has been a death knell for opposing tight ends, having not allowed a score from the position since Week 5 against the Bears. In the eight games since, Minnesota has allowed 23 points total in standard leagues. After putting up a goose egg against Chicago last week, Kroft’s streak of 30 or fewer receiving yards has now reached five games. Attempting to put an end to that streak will be no easy task against the leaders of the NFC North.

Stephen Johnson is 670 The Score’s 2017 Fantasy Football Expert winner. He’s a weekly guest on “Chicago’s Fantasy Football Today,” every Sunday morning during football season from 8.a.m.-9 a.m. CT on WSCR-670 and 670thescore.com/listen. Follow him on Twitter @Stephen_Roto.