On 30 March 1944, Model was placed in command of Army Group North Ukraine in Galicia, which was withdrawing under heavy pressure from Zhukov's 1st Ukrainian Front.
He replaced Manstein, who had fallen out of favour with Hitler.
Despite Manstein's previous victories, the Führer wanted someone whom he anticipated would be unyielding in defence.

On 28 June, Model was sent to rescue Army Group Centre, which had been torn apart by Operation Bagration, the Soviet offensive in Belorussia.
The Ninth Army (Model's old command) and Fourth Army were trapped, and the Red Army was about to liberate Minsk.

Despite the catastrophic situation, Model believed he could still hold Minsk, but this would require Fourth Army to break out of its pocket, and reinforcements to counter-attack the Soviet advance.
The reinforcements, in turn, could only be obtained by pulling back, thus shortening the line and freeing up troops.
The general consensus is that the German position was doomed, regardless of what Model could have done, but Hitler refused to sanction either Fourth Army's escape or a general withdrawal, until it was too late.

Minsk was liberated by the Soviet 1st and 3rd Belorussian Fronts on 3 July, but Model still hoped to re-establish the front to the west of the city, with the aid of divisions from Army Groups North and North Ukraine.

However, German strength was unequal to the task, and he had been driven out of Vilnius and Baranovichi by 8 July.
At the same time, the 1st Ukrainian Front (now commanded by Ivan Konev) and the 1st Belorussian Front's left wing (which had been uncommitted thus far) opened up a fresh offensive against Army Group North Ukraine.
In this battle, the First Panzer Army managed to hold the line east of Lvov using Model's defensive tactics, but was forced to retreat when the Fourth Panzer Army, weakened by the steady flow of units to Army Group Centre, was unable to stem the Soviet penetrations of its front.

Model stopped the Red Army's advance just short of Warsaw by 3 August, setting up a continuous front from south of Shaulyay to the right boundary on the Vistula near Pulawy.

At various times in 1944, Model commanded each of the three major army groups on the Eastern Front, and for a short period in the middle of the year was commanding both Army Groups Centre and North Ukraine simultaneously.
On 30 March 1944, Model was placed in command of Army Group North Ukraine in Galicia, which was withdrawing under heavy pressure from Zhukov's 1st Ukrainian Front. He replaced Manstein, who had fallen out of favour with Hitler. Despite Manstein's previous victories, the Führer wanted someone whom he anticipated would be unyielding in defence.
On 28 June, Model was sent to rescue Army Group Centre, which had been torn apart by Operation Bagration, the Soviet offensive in Belorussia. The Ninth Army (Model's old command) and Fourth Army were trapped, and the Red Army was about to liberate Minsk.
Despite the catastrophic situation, Model believed he could still hold Minsk, but this would require Fourth Army to break out of its pocket, and reinforcements to counter-attack the Soviet advance. The reinforcements, in turn, could only be obtained by pulling back, thus shortening the line and freeing up troops. The general consensus is that the German position was doomed, regardless of what Model could have done, but Hitler refused to sanction either Fourth Army's escape or a general withdrawal, until it was too late.
Minsk was liberated by the Soviet 1st and 3rd Belorussian Fronts on 3 July, but Model still hoped to re-establish the front to the west of the city, with the aid of divisions from Army Groups North and North Ukraine.
However, German strength was unequal to the task, and he had been driven out of Vilnius and Baranovichi by 8 July. At the same time, the 1st Ukrainian Front (now commanded by Ivan Konev) and the 1st Belorussian Front's left wing (which had been uncommitted thus far) opened up a fresh offensive against Army Group North Ukraine. In this battle, the First Panzer Army managed to hold the line east of Lvov using Model's defensive tactics, but was forced to retreat when the Fourth Panzer Army, weakened by the steady flow of units to Army Group Centre, was unable to stem the Soviet penetrations of its front.
Model stopped the Red Army's advance just short of Warsaw by 3 August, setting up a continuous front from south of Shaulyay to the right boundary on the Vistula near Pulawy.
At various times in 1944, Model commanded each of the three major army groups on the Eastern Front, and for a short period in the middle of the year was commanding both Army Groups Centre and North Ukraine simultaneously.
Walter Model