What it means: The Steelers' season is all but over after the defense failed to protect several second-half leads and Ben Roethlisberger couldn't conjure up any late magic at Heinz Field. Roethlisberger was masterful for much of the second half, but he couldn't engineer a drive after twice getting the ball with less than four minutes left in the game and the Steelers needing a score to keep their season alive. The Steelers almost scored a miraculous touchdown on the final play of the game, but Antonio Brown stepped out of bounds at the Dolphins' 11-yard line after a series of laterals. The Steelers are 5-8, and even if they win out, they would need a ton of stuff to happen just to have a chance of sneaking into the AFC playoffs as the second wild card.
Stock watch: The defense provided a big play that gave the Steelers their first lead in a back-and-forth second half, but it also cost them a game that they could not afford to lose. Shoddy tackling and an overall lack of discipline allowed Dolphins such as tight end Charles Clay and backup running back Daniel Thomas to shred the Steelers' defense. They combined for three touchdowns, and Thomas rushed for 105 yards on 16 carries while Clay had seven catches for 97 yards. Clay scored the winning touchdown when neither Troy Polamalu nor Cortez Allen could get the third-year man down after he had caught a pass in the flat.
Switcheroo: LaMarr Woodley returned to the lineup but not the position he has primarily played since becoming a starter in 2008. The Steelers kept Jason Worilds at left outside linebacker, where he had shined in Woodley's absence, and the fourth-year veteran justified coach Mike Tomlin's decision to flip his starting outside linebackers, as Worilds recorded a pair of sacks, including a key one early in the fourth quarter. The Steelers started Woodley but eased him back into action as he split time at right outside linebacker with rookie Jarvis Jones.
An emerging star: Cameron Heyward is playing as well as anyone on the Steelers, and he showed in the first half alone why the third-year veteran has emerged as a cornerstone of the defense. Heyward seemed to be in on every Steelers tackle, and he had six of them in the first two quarters. The former first-round draft pick also sacked QB Ryan Tannehill and batted down a pass in the first half.
Shades of the Iron Bowl: The most exciting play of a rather drab first half happened on the final play -- and evoked memories of the play of the year in college football, a 109-yard touchdown return that Auburn used to beat No. 1 Alabama. It started when Polamalu caught a 52-yard field goal attempt 8 yards deep in the end zone. Polamalu weaved his way to the 30-yard line and threw the ball back to nose tackle Steve McLendon before getting tackled. McLendon flipped the ball to Ike Taylor, and the former college running back made his way to the Dolphins' 40-yard line before getting tackled.
Next up: The Steelers play their final prime-time game of the season next Sunday when they host the Bengals for an 8:30 p.m. ET game. The Bengals improved to 9-4 by beating the Colts, and only an epic collapse will prevent them from winning the AFC North.