When Taylor Decker went down with a torn labrum in his right shoulder in early June, the Detroit Lions moved quickly to acquire two players they hope will fortify their left tackle position.

On the final day of last month's minicamp, a little more than a week after Decker underwent successful surgery, the Lions signed free agent Cyrus Kouandjio and traded a 2018 draft pick to the Los Angeles Rams for Greg Robinson.

Kouandjio is on the non-football injury list as he recovers from off-season hip surgery, while Robinson is expected to take a majority of the first-team reps at left tackle when the Lions open training camp on Sunday.

Robinson has yet to live up to his hype as the No. 2 overall pick of the 2014 draft, when some compared him to a young Orlando Pace, but he did play all of the last two years at left tackle before losing his job this off-season.

Decker, who was placed on the physically unable to perform list earlier this week, is expected to miss about half the season, which could put Robinson in line to play in some of the Lions' toughest games against arguably the best pass rushers on their schedule.

The Lions open the season with games against the Arizona Cardinals, New York Giants and Atlanta Falcons, then play defensive-minded teams like the Minnesota Vikings and Carolina Panthers to open October. Robinson played against four of those opponents last year (everyone but the Vikings) and turned in decidedly mixed performances.

Here's a full breakdown of his five games against the Giants, Falcons, Panthers and Cardinals (twice) to get a sense of what the Lions might have in Robinson.

Week 4 vs. Arizona Cardinals

Robinson played all 59 snaps at left tackle in a 17-13 victory, committed two penalties (holding and ineligible man downfield) and allowed one sack-fumble. Both of his penalties wiped out 27-yard gains, though the holding penalty was a borderline call.

Cardinals outside linebacker Chandler Jones, who had 11 sacks last season and should star for the team again this year, had his way with Robinson much of the day. He beat Robinson for a sack-fumble on the Rams' first drive of the second half, when he stabbed him with his left hand and half-chopped Robinson's arm away to reach quarterback Case Keenum, who was looking for a big play downfield.

Robinson could have easily been called for a couple hands-to-the-face penalties in this game (and, really, in all five of the games I watched of him). As always with film reviews, it's impossible to know what a player's assignments are on any given play or some of the techniques they've been taught, but Robinson was careless with his hands at times and susceptible to inside rush moves.

On running plays, Robinson was often called to block a defender playing in the gap between him and his left guard. This is a tough block for a 332-pound man to make, and predictably he struggled with it at times. His second penalty came on a third-and-3 play in the fourth quarter, when he did a good job running linebacker Alex Okafor wide on a pass rush before Okafor chased down Keenum after Keenum stepped up in the pocket. When Keenum spun out of Okafor's hands, Robinson tried to make up for his mistake by hitting another pass rusher and carelessly crossed the line of scrimmage.

Week 17 at Cardinals

Robinson played all 60 offensive snaps in a 44-6 loss and was not called for any penalties, but the men he was responsible for blocking did share in two different sacks. The Rams, by this time, had gone to rookie Jared Goff at quarterback and their offense, already limited to begin with, was feeble.

Jones and the Cardinals gave Robinson some problems, though Robinson played better than in the first meeting. He made a key block on a Tavon Austin direct-snap touchdown that was called back by a motion penalty — he showed good quickness getting outside the numbers on the block — and he was satisfactory in pass protection despite Los Angeles needing to throw the ball almost from the outset.

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Once again, Robinson was careless with his hands, hitting Jones in the face several times without drawing a penalty. On the third play of the third quarter, Jones and Calais Campbell shared a sack when they ran a stunt on Robinson and left guard Jamon Brown that the offensive linemen failed to communicate on. The second sack was largely of the coverage variety as Robinson knocked Markus Golden down on his initial pass rush only to watch Golden get back up and hit a scrambling Goff from behind to jar the ball loose.

Robinson recovered the fumble.

Week 7 vs. New York Giants (in London)

Robinson played all 79 snaps in a 17-10 loss and was called for four penalties in the game. He drew three holding flags — two were declined, one was off-setting, and all came on the same fourth-quarter series — and a false-start penalty, and gave up half a sack to Jason Pierre-Paul.

Given that Pierre-Paul and Jones were the two best pass rushers Robinson faced in this review of his game, it's no surprise those two gave him the most trouble. Robinson whiffed badly on a block on Pierre-Paul in the Rams' second offensive series, when Pierre-Paul got Robinson off-balance with an inside rush fake. His missed block did not impact the play, but Pierre-Paul shared a sack on the next play, when Keenum stepped up in the pocket to buy time after his first read was covered.

Robinson didn't play poorly for most of the first three quarters, but he struggled in the fourth quarter. Pierre-Paul bull-rushed Robinson almost into Keenum's lap to set up one sack. Robinson was called for a hold (that was declined) on that play and two more times on Pierre-Paul in the series, though one of the penalties was questionable.

Several times, Pierre-Paul beat Robinson inside after showing an outside speed rush, another theme across games.

Week 14 vs. Atlanta Falcons

Robinson played all 72 offensive snaps in a 42-14 loss and drew one holding penalty. He spent most of the day working against Dwight Freeney, who's no longer with the Falcons, and had his best performance of this five-game film review.

Robinson shut down Freeney's patented spin move, and in fact didn't appear susceptible to the spin in any of the games I watched. His one holding penalty did come against Freeney, when he tried to corral the pass rusher by the shoulder as Vic Beasley got a strip-sack rushing from the other side.

Freeney did beat Robinson with a few speed rushes from a nine technique late, but neither rush affected the play. Robinson also was a mixed bag on the goal line. He had a powerful run block on the final play of the third quarter, then let Freeney slip by him into the backfield on the next snap. Fortunately, Todd Gurley broke Freeney's tackle and scored a touchdown.

Week 9 vs. Carolina Panthers

Robinson played all 68 offensive snaps in a 13-10 loss and was not called for any penalties. He did allow one sack, to backup defensive end Mario Addison.

Robinson spent most of the game matched against Addison and Wes Horton. Addison gave Robinson slightly more trouble, though the day was largely a draw. Addison's sack came late in the first quarter, when he drove Robinson back with a left arm to his inside shoulder and recovered from his own slip to corral Keenum.

Some constants: Robinson once again fared well against the spin move, he once again appeared to get away with a hands-to-the-face penalty, and while he played well overall, he suffered a few mental and physical lapses. On one play in particular, Robinson was knocked over by his left guard when he appeared to go the wrong way off the snap.

Final analysis

No one will confuse Robinson for Tyron Smith or even Decker, and the 24-year-old certainly has his work cut out for him if he wins the starting job in Detroit. With Chandler Jones and Jason Pierre-Paul up the first two weeks of the regular season, the Lions will have to give Robinson plenty of help on the outside.

Robinson did show some positive traits. He never really lacked for hustle in any of the games I watched, and he was a solid combo blocker, both on down linemen and when kicking out to block someone on the second level.

Perhaps the trade to Detroit will serve as a wake-up call, but for as big and talented as Robinson is, keep expectations in check.

Contact Dave Birkett: dbirkett@freepress.com. Follow him on Twitter @davebirkett. Download our Lions Xtra app for free on Apple and Android!