X0202 3 2007-07-30 0 0001364541 EAGLE ROCK ENERGY PARTNERS L P EROC 0000806085 LEHMAN BROTHERS HOLDINGS INC 745 SEVENTH AVENUE NEW YORK NY 10019 0 0 1 0 Common Units 7646219 I See Footnote By indirect, wholly-owned subsidiaries of the Reporting Person: 2,674,167 common units held by Lehman Brothers Inc.; 3,590,859 common units held by Lehman Brothers MLP Opportunity Fund LP; and 1,381,193 common units held by Lehman Brothers MLP Partners, LP JOINT FILER INFORMATION: Title of Derivative Securities: Common Stock Issuer & Ticker Symbol: Eagle Rock Energy Partners L P (EROC) Designated Filer: Lehman Brothers Holdings Inc. 745 Seventh Avenue New York, NY 10019 Other Joint Filer Information (all filers share the Reporting Person's address): Lehman Brothers Inc., a Delaware corporation, a direct wholly-owned subsidiary of the Reporting Person. LB I Group Inc., a Delaware corporation, a direct wholly-owned subsidiary of Lehman Brothers Inc. Lehman Brothers MLP Opportunity Associates LLC, a Delaware limited liability company, a direct wholly-owned subsidiary of the Reporting Person. Lehman Brothers MLP Opportunity Associates LP, a Delaware limited partnership, a direct wholly-owned subsidiary of Lehman Brothers MLP Opportunity Associates LLC and general partner of LB MLP Opportunity Fund LP Lehman Brothers MLP Opportunity Fund LP, a Delaware limited partnership. Lehman Brothers MLP Partners, LP, a Delaware limited partnership, a wholly-owned subsidiary of LB I Group Inc. /s/ Barrett S. DiPaolo 2007-08-07