A scan from Newtype magazine that was recently posted to the Internet reveals two new Diamond & Pearl episode titles and gives summaries for them and two other episodes. According to the scan, Shinji will release Hikozaru, who will then join Satoshi. Two episodes later, a title hints that Kojiro will give his Sabonea to Hakutai Gym Leader Natane.
With such extreme changes to the parties of both main characters, it is likely the opening and ending themes will change. No song titles or artists have been revealed.
Translations of summaries provided by PPK.
DP051 - ヒコザルVSザングース！運命のバトル!! Hikozaru vs. Zangoose! Fateful Battle!! will air Oct. 18. Satoshi and Shinji, who have established temporary partnership in the tag battle tournament, win the first round battle. In order to win in the second round, Shinji forces Hikozaru into harsher training. Satoshi sees this and questions Shinji as to why he treats Hikozaru so strictly.
DP052 - タッグバトル！ファイナル!! Tag Battle! Final!! will air Oct. 25. Satoshi and Shinji advance into the semi-finals. However, because Hikozaru cannot adjust its battle status perfectly, Shinji releases it! Upon seeing that, Satoshi tells Hikozaru, "Let's have a journey and become stronger together!" and then captures it.
DP053 - ヒコザルの涙！ Hikozaru's Tears! will air Nov. 1. Satoshi and friends travel to Tobari City, where the next gym is. During the trip, they have a picnic with their Pokémon. However, Hikozaru is confused at the harmonious atmosphere, because this never happened in its journey with Shinji, who gave it nothing but harsh training.
DP054 - ナタネとサボネア！さよならは誰ため！ Natane and Sabonea! A Farewell is for Whom! will air Nov. 8. Satoshi and friends arrive in Tajiki Town and meet Natane, the Hakutai gym leader. She is organizing a promotional Pokémon battle. Team Rocket arrives, and at the suggestion of Natane, Satoshi and friends agree to have a tag battle against the partnership of Natane and Kojiro.