Despite persistent rumours in the summer 2007 transfer window, Ballack denied that he wanted to leave and no such move materialised.
Chelsea left Ballack out of their Champions League squad for the 2007–08 group stage as they realised that his injury would prevent him from playing any useful part and preferred to select the fully fit Steve Sidwell.
The German international had an ankle operation in the summer and Chelsea could not take the risk of him not regaining full fitness before the end of the group stage.
Thus, Ballack could not play in the Champions League before the knockout stages began in February.
The club was only able to select 23 out of a possible 25 players for their Champions League squad due to the new UEFA regulations on "association-trained players" and "club-trained players".
Due to this regulation, Chelsea were also unable to select young player Scott Sinclair and could only pick 23 players as their only "club-trained player" was John Terry.
For this reason, it was deemed unwise to gamble on Ballack being fit at some point.

Ballack made his return to the side in Chelsea's 2–0 League Cup win over Liverpool on 19 December 2007.
Ballack tallied an assist late in the game to striker Andriy Shevchenko.
On 26 December 2007, Ballack made his Premier League return in a thrilling game against Aston Villa which ended 4–4.
He came on for Frank Lampard in the 26th minute after the latter had picked up a thigh injury.
In first-half stoppage time, he won a penalty after being brought down in the box by Zat Knight, which Andriy Shevchenko converted.
In the 88th minute, with the score tied at 3–3, Ballack stepped up to take a free-kick, which he buried into the bottom left corner of the goal, but the match ended in a 4–4 draw.

Ballack captained the Chelsea team in the absence of captain John Terry and vice-captain Frank Lampard in a 2–1 win over Newcastle United on 29 December 2007.
Ballack then played his 50th game in a Chelsea shirt in a 2–1 win against Fulham in which he scored the winning goal for Chelsea.
He also scored the only goal that won the match for Chelsea against Reading to extend the blues' winning streak to a record of nine.
And, on 5 March 2007, he scored again, this time against Olympiacos in the Champions League round of 16 in a 3–0 win.
He scored the winning goal in the 2–0 win in the second leg of the quarter-finals against Fenerbahçe, a victory that secured Chelsea a place in the semi-finals.

Ballack continued to score vital goals and, on 26 April 2008, he scored a header and a penalty to give Chelsea a 2–1 win over Manchester United.
He was named Man of The Match for his performance.
It brought the two teams level in the race for the Premier League title only two matchdays before the end of the season.

The season ended on a low note for Ballack as Chelsea finished runners-up in the League Cup, Premier League and Champions League.
This completed another treble horror for Ballack and his club.
On 29 June 2008, Germany, captained by Ballack, lost to Spain 1–0 in the final of UEFA Euro 2008.
This became the second season in Ballack's career after 2002 that he was runner-up for four major trophies.
Despite persistent rumours in the summer 2007 transfer window, Ballack denied that he wanted to leave and no such move materialised. Chelsea left Ballack out of their Champions League squad for the 2007–08 group stage as they realised that his injury would prevent him from playing any useful part and preferred to select the fully fit Steve Sidwell. The German international had an ankle operation in the summer and Chelsea could not take the risk of him not regaining full fitness before the end of the group stage. Thus, Ballack could not play in the Champions League before the knockout stages began in February. The club was only able to select 23 out of a possible 25 players for their Champions League squad due to the new UEFA regulations on "association-trained players" and "club-trained players". Due to this regulation, Chelsea were also unable to select young player Scott Sinclair and could only pick 23 players as their only "club-trained player" was John Terry. For this reason, it was deemed unwise to gamble on Ballack being fit at some point.
Ballack made his return to the side in Chelsea's 2–0 League Cup win over Liverpool on 19 December 2007. Ballack tallied an assist late in the game to striker Andriy Shevchenko. On 26 December 2007, Ballack made his Premier League return in a thrilling game against Aston Villa which ended 4–4. He came on for Frank Lampard in the 26th minute after the latter had picked up a thigh injury. In first-half stoppage time, he won a penalty after being brought down in the box by Zat Knight, which Andriy Shevchenko converted. In the 88th minute, with the score tied at 3–3, Ballack stepped up to take a free-kick, which he buried into the bottom left corner of the goal, but the match ended in a 4–4 draw.
Ballack captained the Chelsea team in the absence of captain John Terry and vice-captain Frank Lampard in a 2–1 win over Newcastle United on 29 December 2007. Ballack then played his 50th game in a Chelsea shirt in a 2–1 win against Fulham in which he scored the winning goal for Chelsea. He also scored the only goal that won the match for Chelsea against Reading to extend the blues' winning streak to a record of nine. And, on 5 March 2007, he scored again, this time against Olympiacos in the Champions League round of 16 in a 3–0 win. He scored the winning goal in the 2–0 win in the second leg of the quarter-finals against Fenerbahçe, a victory that secured Chelsea a place in the semi-finals.
Ballack continued to score vital goals and, on 26 April 2008, he scored a header and a penalty to give Chelsea a 2–1 win over Manchester United. He was named Man of The Match for his performance. It brought the two teams level in the race for the Premier League title only two matchdays before the end of the season.
The season ended on a low note for Ballack as Chelsea finished runners-up in the League Cup, Premier League and Champions League. This completed another treble horror for Ballack and his club. On 29 June 2008, Germany, captained by Ballack, lost to Spain 1–0 in the final of UEFA Euro 2008. This became the second season in Ballack's career after 2002 that he was runner-up for four major trophies.
Michael Ballack