Conversation so far:
When did Clemens return to the yankees?
Clemens made his 2007 return on June 9.
How did he perform with the yankees?
On July 2, Clemens collected his 350th win against the Minnesota Twins at Yankee Stadium.
did he play in the postseason?
CANNOTANSWER.
how long was he with the yankees?
Clemens finished the 2007 regular season.
Did anything exciting happen while he was with them?
Clemens was forced to leave Game 3 of the 2007 ALDS.
Why was he forced to leave?
a hamstring injury.

Question: Was this a big deal?
Self-contained rewrite: Was Roger Clemens's hamstring injury a big deal?