What does the "grade" of a muscle tear actually tell you?

A grade ranks how badly the muscle is damaged

The "grade" that turns up in reports of a muscle tear is a way of splitting severity into three levels, based on how much tissue has been damaged and how much strength and function have been lost. It is an old scale, in use since the 1960s. The precise definitions vary a little from one classification to the next, but broadly, grade 1 means a small number of fibres have been stretched or torn: it hurts when pressed, but strength is preserved. Grade 2 means some of the fibres have ruptured, the pain is sharper and there is a clear weakness when the player tries to push through it. Grade 3 is a complete tear of the muscle, with loss of function and sometimes a dent you can feel through the skin. The clinical guide that FC Barcelona's medical department published in 2009 calls grade 1 microrrotura fibrilar, grade 2 rotura fibrilar and grade 3 rotura muscular. The rotura fibrilar you see so often in the Spanish press would be a grade 2 under that guide's scheme, but clubs and reporters frequently attach a separate grado I or II to rotura fibrilar, so it is better not to judge severity from the words alone.

Recovery estimates are also given along these three levels. The same Barcelona guide gives 3 to 15 days for grade 1, 3 to 8 weeks for grade 2 and 8 to 12 weeks for grade 3. Figures closer to what actually happens come from a UEFA study. Of 516 hamstring injuries at 23 European clubs, 207 had an MRI with the findings recorded on a form. Sorted into four grades from 0 to 3, with 0 for scans that showed nothing, the average lay-off was 8, 17, 22 and 73 days respectively. Grade 3 was rare at just 3%, and 70% were grade 0 or 1, with no fibre tear visible on the scan.

No single rulebook decides what grade 2 means

The first thing to know is that there is no single, worldwide way of assigning a grade. The old 1-to-3 scale was originally decided in the consulting room, by feel and by strength testing, and once MRI became routine, several other schemes were built around what you count on the image. The Munich consensus classification, drawn up by an expert group in 2013, puts injuries with no fibre tear at 1 and 2 and those with a tear at 3 and 4. BAMIC (the British Athletics Muscle Injury Classification), created by British Athletics' medical team in 2014, grades from 0 to 4 by the cross-sectional area and length of the oedema visible on MRI, how far the fibre architecture has broken down, and so on. For grades 1 to 4 it then adds a letter, a, b or c, for whether the injury sits at the fascia, within the muscle or at the junction between muscle and tendon, or inside the tendon itself. A review that gathered research from 2010 to April 2022 found 24 different classifications across 37 studies.

So the same "grade 2" means a partial fibre tear on the old three-level scale, a moderate injury defined by MRI findings under BAMIC, and, on the Munich classification, an injury with no tear at all. When a club or a newspaper says "grade 2", which scheme's 2 it is almost never stated. The number alone cannot be converted into weeks.

Tendon involvement tells you more than the grade

Grade and length of absence do rise together. But the spread is enormous. In the UEFA study above, the gap between 17 days for grade 1 and 22 days for grade 2 is only five days, and the standard deviations, 10 and 11 days, are bigger than the gap itself. A study that followed 169 injuries at one professional club over ten seasons found BAMIC 2b ranging from 0 to 70 days and 3c from 3 to 191 days. Within a single grade, the lay-off runs from a few days to a few months.

What I would rather look at than the number is whether the damage reaches the tendon. A study of 61 hamstring injuries at one English club over eight seasons found that among BAMIC grade 2 injuries, the ten 2c cases, where the tendon running through the muscle was involved, had a median of 37 days before full return to team training, against 22 days for the 16 2b cases, where it was not. Recurrence came in 5 of the 13 injuries with tendon involvement and 5 of the 40 without it, excluding grade 0. The numbers are small, but the difference was significant. Which muscle matters too. In a UEFA study of 255 injuries, the recurrence rate for the biceps femoris within the hamstrings was 18%, an order of magnitude away from the 2% for the semimembranosus and semitendinosus. How much longer tendon involvement keeps a player out varies from study to study, and one report concluded that even where a difference exists, the overlap between individuals is so large that it is hard to use for prognosis. Even so, one summary that looked across several classifications found only two findings that were tied to lay-off length: nothing visible on the MRI, and involvement of the tendon.

Atlético's statements do not say when a player returns

With those figures in mind, the way Atlético words its official statements starts to make sense. Going back through the official announcements since 2025, I traced ten muscle injuries. Seven of them located the injury no more precisely than "a muscle injury in the muslo", the thigh, and most closed with the line that the player's progress will decide when he returns. Not one of the ten gave a number of weeks or a target match. The announcements that did touch on grade used words such as bajo grado and grado moderado; the numbers 1 and 2 did not appear. The "three weeks" or "one month" you read in the press are not figures written in the club's official statement, at least.

Line up last season's cases and you can see how much those estimates swing. On 3 December 2025, Álex Baena and José María Giménez were announced with the identical wording, "a bajo grado muscle injury", and the press put both at around two weeks. Both were first called up again for the Real Sociedad match on 4 January, 32 days after the announcement. Antoine Griezmann was announced on 23 January with the same low-grade wording, started against Betis 13 days later and scored in the 62nd minute. Pablo Barrios went the other way: his announcement of 26 April carried no grade at all, the press guessed anywhere from ten days to a month, and he had still not returned by the final match of the season.

Coming back is not the same as being healed

One more thing changes: how you look at a player once the absence is over. UEFA's figures across 21 seasons show that 18% of hamstring injuries are recurrences, and seven in ten of those happen within two months of returning to matches. In the same UEFA data, covering muscle injuries as a whole, the lay-off for a recurrence was longer than for the first injury.

So for two months or so after a player is back in matches, I have decided not to be surprised if he keeps coming off the bench, or if he is taken off again in the match where he returns to the starting eleven. There are also substitutions that are hard to read from the outside for reasons other than injury. When Barrios was taken off in the 78th minute against Bodø/Glimt last January and the Metropolitano booed, Simeone explained at his press conference two days later: "Pablo is a very important player for us. We play every three days and there is no replacement like him. So we try to protect him, so that he keeps playing and can be there for every match" (Cadena SER). As with the injury announcements, I think there are things inside the team that cannot be seen from outside.