Udoji arrives at Priory Lane from Bostik League North side Maldon & Tiptree but he has plenty of experience at Boro`s level, including winning the National League South with Bromley and Salisbury City, and through a loan spell at Tonbridge Angels.
The 28-year-old has also worn the colours of Bishop's Stortford, Havant & Waterlooville, Stafford Rangers, Portsmouth and the sadly now defunct Rushden & Diamonds, and also attended the Glenn Hoddle Academy in Spain.
Udoji met the squad on Thursday evening and goes straight into the squad for tomorrow's trip to Gloucester City.
Johnson has returned to Priory Lane following his departure from Bostik South side Hastings United.
Johnson needs no introduction to Boro fans through his long association with the club - coming up through the ranks of the under-18's to feature at National League and South levels for both Garry Wilson and Tommy Widdrington, his versatility, desire, and his goals making him a hugely popular figure.
Johnson left Priory Lane for National League side Maidstone United but moved on to the Pilot Field in October 2015 prior to his re-signing at Boro.
(Photo: Simon Johnson - DJ Stotty Images)