In East London Proteas ODI skipper Temba Bavuma may have responded to 144 problems, despite not being on the winning side against the West Indies on Saturday, but there are two outstanding issues that may dog his team: Tabraiz Shamsi and the over-rate.Shamsi, in particular, is proving to be a bowling headache, especially with Keshav Maharaj's absence set to be a long one after rupturing his Achilles tendon.Maharaj and Shamsi were swopping the bowling slot for home games, with Maharaj starting to get preference due to his better batting and leadership skills.READ | Bavuma rues Proteas' middle order batting collapse: 'It's criminal in a run chase'If Maharaj was fit, there was a high probability that Shamsi was not going to play, meaning this series affords him another opportunity to bowl himself back into form, and he will be needed by the Proteas, not just for Tuesday's third ODI in Potchefstroom, but the critical two ODIs against the Netherlands on 31 March and 2 April.The distinct lack of form since the India ODIs in Paarl last year isn't just a growing concern, but one that can and will affect selection going forward.There's a growing need to build batting depth from SA's all-rounder perspective that, at some point, will see a bowling strength slightly compromised.MATCH REPORT | Temba Bavuma's stunning century in vain as Proteas lose second ODI to West IndiesBjorn Fortuin and, to an extent, George Linde not only afford safer batting alternatives, but they are also more consistent bowling options that may ask pressing questions about Shamsi's current ability.Bavuma, like any skipper who values his match-winners, was unequivocal in his support for Shamsi, despite his current form."A guy like Shamsi is an important