Despite the plethora of moves that Borussia Dortmund Sporting Director Sebastian Kehl has made to improve his club’s squad this offseason, there’s still at least one more glaring hole to be filled. With star Norwegian striker Erling Haaland on his way to Manchester, Borussia Dortmund find themselves in desperate need of a new forward to lead the line. Although the club has been linked to numerous players at the striker position this summer, including Hugo Ekitike, Adam Hlozek, Patrik Schick, and others, the shortlist seems to have narrowed down to two players: Sebastian Haller of AFC Ajax and Sasa Kalajdzic of VfB Stuttgart.
Both players are proven goalscorers, are in or near their primes, and fit the bill of a strong-finishing, physical, intelligent striker that can both score and set up goals. Either one would vastly improve the squad, but the question is: who would improve it more?
These two players are very similar in certain areas and wildly different in others. The purpose of this article is to break down each of these areas and try to make a determination as to which player BVB should prioritize.
Since taking over as Sporting Director for Borussia Dortmund, Sebastian Kehl has made a very concerted effort towards signing players that are either immediately entering, or are already in, their primes. The bulk of the research on the subject suggests that the average player’s quality as they age tends to follow more or less of a bell curve that peaks roughly between 25-27, with forwards peaking earlier in their careers than defenders. Of the four “big” transfers that BVB have made so far, three of four— Karim Adeyemi (20), Salih Özcan (24), and Nico Schlotterbeck (22) could firmly be said to be ahead of their predicted peaks, while Niklas Süle (26) should theoretically be peaking around now.
Kalajdzic (24) and Haller (27) aren’t too far apart age wise, but Kalajdzic being a few years younger is definitely a point in his corner. Assuming whoever Sebastian Kehl ends up buying sticks around for a few years, he’ll want to ensure that they’re able to maintain a high level of play as long as possible. I don’t think that’ll be too much of a problem for Haller, especially for the next 2-3 years, but it’s still something to consider.
#2: Physical Characteristics
To borrow a highly scientific term, both Sebastian Haller and Sasa Kalajdzic could accurately be described as “big lads.” Haller is 6’3” (190 cm), while Kalajdzic is the tallest player in the Bundesliga at 6’7” (200 cm). As such, both players are nightmares to deal with physically, both in the air and with the ball at their feet. Kalajdzic is above the 90th percentile among forwards in Aerial Duels won per 90 minutes, while Haller just makes the top quartile.
Because both players are so large, neither of them is particularly quick. About the best metric we have to confirm this would be the Bundesliga’s AWS sprint speed database. This season, Kalajdzic’s top speed this season was 32.36 km/h, making him the 283rd fastest player in the Bundesliga. To further put his speed in perspective, the closest BVB player to him in pace was Julian Brandt, whose max speed was 32.39 km/h.
Unfortunately I couldn’t find sprint speed data for the Eredivisie, and AWS didn’t collect sprint speed data when Haller was in the Bundesliga, so I’ll have to resort to what I can judge from watching footage of him. The sense I get is that Haller might be a tad quicker than Kalajdzic, but not by much. Like Sasa, he won’t be leaving many defenders in the dust in a straight sprint.
Overall, I’d say both players are fairly similar physically. Kalajdzic is slightly more dangerous in the air, but that’s about it.
#3: Playing Style
Because they’re so similar physically, both players have somewhat similar playing styles, although they aren’t identical. For the purpose of brevity I’ll focus in on what I consider to be their key strengths, but it’s worth noting that neither player is particularly one-dimensional. They can score in a multitude of situations, including off set-pieces or on counterattacks.
With Kalajdzic’s height you’d think he’d fit the “target man” archetype to a tee. While he scores his fair share of headers without question, it would be unfair to box him in as an aerial threat only. Despite his looming stature, he’s actually very good at controlling the ball with his foot in tight spaces, and equally good at timing runs and finding open space, even when he’s being tightly marked. His finishishing, both with his head and his feet, are solid as well. Who could forget this absolutely ridiculous goal he scored against BVB in 2021?
Like Kalajdzic, Haller uses his clever positioning to find small pockets of open space around defenders, and once he receives a pass he’s almost impossible to nudge off the ball. What I really like about Haller is his holdup play. He’s very good at receiving the ball and holding off two or three center backs before picking an easy pass to an open man. It’s for this reason that he has racked up so many assists throughout his career, in addition to his exceptional goalscoring record.
To keep things fair, here’s a clip of Haller scoring a header, also against BVB:
While both players are similar in size to Erling Haaland, they couldn’t be more different in playing styles. Haaland thrived when he had the time and space to barrel past opponents and unleash his cannon of a shot. He tended to struggle more when wriggling for space in a crowded 18-yard-box, while it’s this precise area where Haller and Kalajdzic tend to thrive. Both are extremely intelligent players who have an uncanny ability to find open space, and make the most of it when they receive the ball. It will be a change in style for sure, but it could be just what Dortmund need.
Let’s stop beating around the bushes and talk about these two players’ goalscoring records.
In addition to his phenomenal numbers with Ajax over the last two years, Sebastian Haller’s 2018-19 season with Eintracht Frankfurt will surely have BVB fans licking their chops. He scored at the rate of about a goal or assist every game over about 2,200 minutes of Bundesliga action. I didn’t include the Champions League in the table above because Kalajdzic never played in that particular competition, but it’s worth noting that Haller also had 11 goals in only eight appearances in the Champions League last season, including two goals and an assist in two matches against Borussia Dortmund.
However, there are reasons to pause over Haller’s goalscoring record. His time at West Ham United could generally be described as a failure, and the fact that he struggled against stiffer competition could be a cause for concern. Further, his scoring rate in the Eredivisie could be chalked up to the league’s shoddy defending. He’s far from the first player to light up the Dutch league. Donyell Malen averaged 0.99 G+A/90 with PSV Eindhoven a year before joining BVB, and he struggled quite a bit upon moving to the Bundesliga. I’m not saying Haller would struggle too; unlike Malen, he actually has a proven track record in the Bundesliga, if only for one season.
Kalajdzic hasn’t quite hit Haller’s raw scoring rate, although he did come somewhat close in the 2020-21 season when he racked up 16 goals and 5 assists, making him one of the most productive players of the season. His expected goal and assist totals (9.0 and 3.5, respectively) suggest he benefited mightily from what could be called lucky finishing. His fortune actually swung in the other direction this last season, with him underperforming his xG and xA slightly, leading to his unimpressive goal and assist totals (injuries also had much to do with that).
So overall, I think Haller has the better goalscoring record, although it’s much closer than some of the raw totals would have you think. I can empathize with those who have reservations about Haller’s numbers in the Eredivisie. Further, Haller put up his numbers with largely elite teams or upper tier clubs, while Stuttgart have been either mid-table or relegation fighters in Sasa’s two seasons with them.
At the end of the day, though, Haller takes the edge. Aside from his time in Austria, Kalajdzic has only had one truly great season, and it’s unclear that he could sustain that level of finishing over a long period of time. I’m inclined to remain skeptical until he proves himself over a longer period of time.
I’m getting long-winded, so I’ll keep this one brief. Sasa Kalajdzic will probably cost around €25 million give or take, while Haller would be more pricey, probably around €35-40 million. As Dortmund will probably make at least one more signing this summer, preferably at left back, that’s an important consideration to take.
#6: Injury History
Given BVB’s experience with injuries last season, this has to be a consideration as well. According to Transfermarkt, Sebastian Haller’s career, in recent years at least, has been largely unaffected by serious injuries. He’s missed a few games here and there like any other player, but nothing major. Kalajdzic, on the other hand, has suffered multiple serious injuries, including an ACL tear and a Syndesmotic (ankle) tendon tear. These injuries are both serious and, at least slightly more likely to reoccur once they’ve happened. I don’t think they should rule out Kalajdzic entirely, but they’re at least a point against him.
First of all, I would be ecstatic if BVB signed either of these players. Both are massive and strong but also technically and positionally gifted, and I think either one would score a whole bucket of goals.
Overall, in my opinion Sebastian Haller is the more proven player, and would best fit the moves that Sebastian Kehl has made this summer. With Bayern Munich in transition mode, potentially losing both Robert Lewandowski and Serge Gnabry, this could be a real chance to win a title, and signing a complete package like Haller could be what tips Dortmund over the edge. While his transfer fee is definitely nothing to scoff at, money has, for whatever reason, not been much of an issue this summer, so if it’s there, I say we use it.
That being said, Kalajdzic is younger and has loads of raw talent, and could be acquired for cheaper. He could easily end up being the signing with better long-term value. I still think we should pursue Haller, but if we do end up going with Kalajdzic, I will be more than happy.