Probably, but all small parties in Germany find themselves occasionally flirting with the 5% mark.  I also think that they benefited somewhat from the perception that Red-Green was dead anyways. In a tight race some potential Linke voters would presumably hesitate about de-facto voting for either a grand coalition or a right wing one.

In general the Linkspartei throws a spanner into the functioning of parliamentary politics: it's harder to get to fifty out of 92 than out of 100.