Angus Bell is one of six players to have picked up an injury in Friday's defeat by Leinster [Getty Images]Ulster continue to count the cost of Friday's 29-21 defeat by Leinster in the United Rugby Championship [URC] with six players added to the injury list for this Saturday's trip to face Munster at Thomond Park [17:30 BST].Angus Bell (foot), Scott Wilson (ankle), Tom O'Toole (hand), James Hume (neck), Jude Postlethwaite (hand) and Bryn Ward (shoulder) have all been ruled out after picking up injuries against Leo Cullen's side.They join a list of unavilable players that already includes Nick Timoney (hip), James McNabney (knee), Rob Herring (calf), Robert Baloucoune (elbow), Rory McGuire (shoulder) and Stewart Moore (knee).Ulster dropped to fifth in the URC standings following last week's defeat, one point above Munster as the season enters its final three rounds of games before the play-offs."Not winning at home was a big moment for us, but then add the guys who have picked up knocks," Ulster coach Richie Murphy told BBC Sport NI."There will be a bit of pressure on our squad depth this week, but that's exciting as well with everyone wanting to put their hand up for what is ahead."It's going to be interesting, not going to be easy, but it is an exciting couple of weeks ahead."Murphy's side have a home European Challenge Cup semi-final against Exeter Chiefs to look forward to on Saturday, 2 May as they seek to end their 20-year wait for silverware and while there is "no timeline" but feels some have a "really good chance of playing next week".One player who may feature this week is Michael Lowry who has returned to full training and his availability for the trip to Limerick will be assessed throughout the week."Mikey has had a really tough run over the last while and at the start of the season, we played some of our best rugby with him in the team," Murphy continued."He played for Ireland 'A' against Spain and picked up an injury. From that moment, he's struggled for fitness, but was flying around in training today and a great addition to our squad for the next few weeks."'Massive challenge awaits in Thomond Park'Murphy has urged his players to "get back on the horse" against Munster [Getty Images]Murphy has urged his players to "get back on the horse" following Friday's defeat by Leinster.Ulster trailed 29-0 early in the second half and while they managed to get to within eight points at the final whistle, they came up empty handed.There is still plenty to play for with a top-four finish in the URC regular season a possibility which would seal a home quarter-final, plus next week's Challenge Cup semi-final to come.This week's game in Limerick will be their final regular season away game but one that is vitally important as the play-offs approach."If you told us we'd get to this stage of the year with a semi-final to look forward to and three games to go in the league looking to make sure we stay in the top eight or even an opportunity to get into the top four, we'd be massively excited," Murphy said."We know there are still parts of our game we need to improve and we're working hard in the background."They [Munster] have had a break after a tough run of games. People have said they haven't been good, but if you look at the number of games they've played away from home, it's been huge so it will be a massive challenge for us in Thomond Park this week."