During Carlo Ancelotti’s tenure as Bayern Munich manager, Javi Martinez was most often as a center back alongside Mats Hummels, especially during Jerome Boateng’s lengthy injury spell. His most natural position, however, is a central defensive midfielder and since Jupp Heynckes has taken charge of the club, that’s where he’s utilized the Spaniard. From a total of four appearances since Heynckes took charge, Martinez has started three times across all competitions and has acted as the anchor just in front of the backline. More importantly, three of the five games Martinez has started in the league in total, Bayern have kept clean sheets.
After some late match heroics against Celtic in the Champions League by virtue of a match-winning header in the 77th minute (Bayern defeated Celtic 2-1), Martinez’s teammates, along with Heynckes, gave him plenty of praise, expressing how important he is in his deeper midfield role. The Bayern manager highlighted how much the squad has been stabilized with Javi playing in the midfield role (via Bundesliga):
Javi has played in central defence before, but I have a rather different opinion. Since he's been playing in midfield we've improved our stability and the quality of our defensive work. He's also very dangerous from set pieces, and the way in which he scored the excellent winning goal [vs. Celtic] - well, not many players can do that.
Arjen Robben echoed Heynckes’ view, and also made sure to reference Javi’s effectiveness during Heynckes’ previous tenure as Bayern boss:
Javi's incredibly important, of course. He played more as a centre-back last season and now he's back in defensive midfield, playing very well when we don't have the ball. He also got the winning goal against Celtic, so you can only give him credit. He's so important in that defensive midfield role, just as he was during our very successful previous spell with Jupp Heynckes.
Keeper Sven Ulreich struck a rather thankful tone when he was asked about Martinez’s presence just in front on Bayern’s defensive line, suggesting that he’s a chief contributor to Bayern recording clean sheets:
Javi is fiercely important, a key factor in why we've been less likely to concede over the past few weeks. He gives us greater stability in defence. He makes very intelligent runs and closes down the space.
Javi as a CDM vs. Javi as a CB
Though no season has quite compared to the famous treble-winning season of 2012/2013, Bayern did cumulatively collect a fair amount of silverware between the tenures of both Pep Guardiola (2013-2016) and Carlo Ancelotti (2016-2017). Under Heynckes, Martinez was almost exclusively utilized as a central defensive midfielder, and it was Guardiola who eventually decided to try and shift him to a center back role at times.
Though he was quite hampered with injury problems between 2013 and 2015, Martinez still recorded the highest tackles per match ratio (2.6) and interceptions per match (1.6) in the 2013/2014 Bundesliga campaign, most often being deployed as a center back. Despite the impressive defensive contributions, he failed to record a single goal or assist during that campaign and didn't get as many opportunities to showcase his offensive strengths. Under Ancelotti in the 2016/2017 league campaign when he was predominantly used as a center back, it was much of the same as far as the lack of balance between defensive and offensive contributions: He averaged 1.7 tackles per match (5th most in the squad that season), 2 interceptions per match (4th most in the squad that season), and only recorded one goal and one assist.
By stark contrast, in the treble winning season of 2012/2013 under Heynckes, Javi struck a strong balance between his defensive and offensive statistics playing as a holding midfielder. In the league, he averaged 2.3 tackles per match, 1.9 interceptions per match, and he also recorded 3 goals and 3 assists, boasting a pass completion rate of 87.7%. His stats were equally as impressive in the Champions League that season as well, averaging 3 tackles per match, 3.8 interceptions per match, and boasting a pass completion rate of 87.7%, equal to his mark in the league.
Fast forward to 2017 since Heynckes has taken charge after Ancelotti's departure and Javi is back to his old self playing in Bayern's midfield. Thus far, he's cumulatively averaged 1.8 tackles per match, 1.8 interceptions, 1.4 clearances, and has also provided and assist, boasting a pass completion rate of 88.4% from a total of 5 appearances. In the Champions League group stages [thus far], he's averaged 1.3 tackles per match, 2 interceptions, 4 clearances, produced a pass completion rate of 86.2%, and also scored the all important match winner against Celtic in Glasgow.
Clearly, Heynckes has got Martinez firing on all cylinders at the moment and it's contagiously uplifted the rest of the squad with how much he brings to the game from a central defensive midfield role, on both sides of the ball.
A parting gift that emulates Javi's commitment: